Product: Credit card or prepaid card

I am writing to you to dispute {$1000.00} of new purchases that appeared on my billing statement that ended XX/XX/XXXX. There have been several issues with this account and numerous calls to Customer Service. I am going to lay out the entire history of the issues that have occurred over the past few months. 
1. I have had to call every month to have payments applied when I have regular transactions and promotional purchases. I have several credit cards and you are the only one where this is not an automatic thing. 
a. It seems that you hope that your customers wont be diligent about their accounts so that you can charge them more interest. 
b. I had to do this after I received my statement ending XX/XX/XXXX. I was assessed {$2.00} in interest. I called the second that I downloaded the statement to have the payments applied correctly and the interest charge reversed. This reversal wasnt done until my second call on XX/XX/XXXX. It appears on my statement ending XX/XX/XXXX. 
2. I had a large purchase that I needed to make to my vet ( XXXX XXXX XXXX XXXX ) so I called to find out what dollar amount I needed to transfer so that my payments would not be held. This is a practice where XXXX XXXX gets ACH payments but will not adjust the available balance for at least 10 days. It was critical that I have the funds available to pay for this large purchase. I was told that the amount was {$500.00}. 
a. I scheduled {$500.00} payments to take place on XX/XX/XXXX ( before due date ), XX/XX/XXXX ( payment due date ), XX/XX/XXXX ; and a payment of {$170.00} scheduled for XX/XX/XXXX. This would have provided the available balance that I needed to cover the purchase that I needed to make. 
b. I had to call Customer Service every day starting XX/XX/XXXX because my available balance was not changing. After 2 days of calls, an agent adjusted my available balance for 1 of the {$500.00} payments. I couldnt have Synchrony bank double dip by taking funds from my account but not allowing me to have access to those funds. On the suggestion of the Customer Service Manager, I cancelled the XX/XX/XXXX payment and had my bank reverse the ACH that occurred on XX/XX/XXXX. This was so that I could cover the purchase at XXXX XXXX between my bank account and my Care Credit card. As I stated each time I have called Customer Service every day since XX/XX/XXXX, all of the cancelled payments and reversals would have been reversed if XXXX XXXX would just give me access to my funds. From the time that I opened by account in XX/XX/XXXX until XX/XX/XXXX, I had never had a payment returned or rejected by my bank. Had I been given access to my funds, none of the subsequent issues with this account would have happened. 
c. When I received my statement ending XX/XX/XXXX, I noticed that XXXX XXXX had chosen to mark the payment that was on time ( XX/XX/XXXX ) as reversed and had inexplicably shown a payment posting on XX/XX/XXXX ( no payment was made on that date ). This was after the due date so I was assessed a late fee and interest on purchases. 
d. I called to have the late payment and interest charges reversed because the payment was not late. I also followed up because the {$2.00} of interest charges that were assessed on my statement ending XX/XX/XXXX had not yet been reversed. These were my only requests regarding this account. I was told that it could take up to two billing statements for my account to be corrected. 
e. As of the statement ending XX/XX/XXXX my ending balance according to my statement was {$3500.00} and my records show a balance of {$3400.00}. The discrepancy between my Synchrony statement and my records was only {$44.00} which is detailed below : f. I have also included an XXXX spreadsheet starting with statement ending XX/XX/XXXX to show the detail behind the {$3400.00} balance from my records since, at this point, the balance was only comprised of promotional balances and one regular purchase with a balance of {$120.00} ( original purchase {$130.00} ). Again, the only difference between my records and Synchronys was {$44.00} in interest and late fees that been incorrectly assessed on my account. 
3. When I received my statement ending XX/XX/XXXX, I printed out the statement but didnt call Customer Service. Although the statement didnt match my records, I was going to give them time to get the issues from the statement ending XX/XX/XXXX resolved. 
a. I can see the interest charges of {$2.00} and {$4.00} reversed along with the late fee of {$38.00}. And the payments that I made ( {$500.00} on XX/XX/XXXX and {$160.00} on XX/XX/XXXX ). 
b. The difference between the statement ending XX/XX/XXXX and my records is {$1100.00}. Even though the detail is provided, I am at a loss to explain where this most of this activity is coming from. Obviously, someone at Synchrony bank was making some goofy calculations. I have no idea why they were doing so. The end result is that my balance went up by {$1000.00} due to new purchases when no new purchases were made. Even if I wanted to make any new purchases, I would not have been able to because my account was over the limit. 
c. This overstatement of my balance caused my minimum payment to be overcalculated. I made my payment on XX/XX/XXXX of {$97.00} because this will ensure that my remaining promotional balance that expires on XX/XX/XXXX will be paid on time. 
4. When I received my statement ending XX/XX/XXXX, I again called Customer Service. It had been enough time for all of the issues to be rectified. The difference between my records and the Synchrony statement is {$1000.00}. 
a. Detail is : b. On XX/XX/XXXX Customer Service agreed to reverse the interest charges and late fees assessed due to the minimum payment being incorrectly calculated because the outstanding balance is overstated by {$1000.00}. I will expect to see those charges reversed on my XX/XX/XXXX statement. 
c. No one can adequately explain where the additional {$1000.00} added to my statement ending XX/XX/XXXX came from. I was told that it was because I had requested a re-allocation of payments in XX/XX/XXXX. I did no such thing. Plus, even if I had, the outstanding balance on this account would be unchanged. 
d. In addition, the promotional balances on my account are extremely inaccurate. I have enclosed detail of how the payments should have been logically applied. What I find most concerning is that my statement ending XX/XX/XXXX shows my promotional balances that is much higher than the initial purchase amount for the transaction dated XX/XX/XXXX. When I pointed this out to the Customer Service Manager on XX/XX/XXXX, I was told that this was because they updated information from the doctors office. I stated that this wasnt possible and I have enclosed a copy of that original receipt for that transaction.