Product: Credit card

I am writing today to file a complaint against PayPal Credit. I believe their practices to be deceptive and fraudulent, having wrongfully charged me late fees and interest charges over a 10 month period. 
On XXXX/XXXX/XXXX I made a purchase of {$670.00} with my PayPal Credit ( PPC ) acct. My billing cycle date was set as the XXXX of each month, and a payment due date XX/XX/XXXX. On XXXX/XXXX/XXXX I made my first payment of {$66.00} towards the balance, and set up a a further 9 mos. automatic payments to post on the XXXX of each month, with the final XXXX on XXXX/XXXX/XXXX. 
For each month from XXXX XXXX to XXXX XXXX I received XXXX emails from PPC ; the first making me aware of an upcoming payment, and the second to let me know it had been received. 
On XXXX/XXXX/XXXX I received an email titled 'Time Sensitive PPC acct information ' which informed me that I missed an acct payment. Logging into my acct I was shocked to see an acct. balance of {$340.00}. For each month I had been made payments I had also been charged a late fee and interest which accted for the balance. 
Surprised, I called PayPal ( PP ) and was told that because my payments were received between my due date ( XX/XX/XXXX ) and my cycle date ( XX/XX/XXXX ) their system was not sure which month to apply the payment to, which was 'Probably ' the reason for the fees. The service rep. offered to refund XXXX months fee for my 'good faith payments ' but for anything more I 'd have to write a letter to their investigations dept. explaining my case. 
This was made more shocking by the fact that prior to XX/XX/XXXX. I had NEVER been able to log in to my acct. page, and save for a single statement email I received on XXXX/XXXX/XXXX I was NEVER able to see my acct balance. ( I believe the only reason I received this lone email is b/c after submitting several help requests to PP I was prompted to change my acct password on XXXX/XXXX/XXXX ) In PP the only link to anything resembling a credit page was a 'Bill Me Later ' link, that when clicked would link to a page informing you that that Bill Me Later ( BML ) was now PPC XXXX along with a link to my PPC page, which looped back to my main PP acct page. This happened no matter how I tried to access the acct - whether it was through links in the monthly payment emails, going directly to paypalcredit.com, or billmelater.com - they all sent me through the same loop between PP and BML, and never to an acct. page where I could see acct. statements. Even the lone statement email I received on XXXX/XXXX/XXXX had a link included that was titled 'Bill Me Later ' bringing me to the same loop. To this day, when I try and access my acct page I still get this loop! The ONLY time I was able to access my acct. page was when I was informed of a missed payment in XX/XX/XXXX, and they were asking for more money. 
2 wks after sending the letter re : my case I received a msg telling me my case had been resolved and that I would see a refund, if any in my acct. A wk later I called and was told by an agent told that they found I was not owed a refund. Pressed as to why I was told that b/c my payments were made btwn my due date and cycle date they WOULD count towards my balance, but they would NOT count towards a due date - neither the month the payment was made in, or the previous month they claim I was 'late ' to paying. Confused, I asked if that effectively meant there were 5-6 days of every month that I could not make a payment and have it count towards my due date, to which he replied YES, and that I should know, because that is how all credit accts the world over work! Furthermore, he told me it was my responsibility to check my statement every month, and that I should have received statement emails every month. 
Pressed further he offered to run an 'email check ' to make sure all of the emails were in fact sent, and received. Lo-and-behold that report came back saying I had in fact received all of those emails, and for that reason they could not refund my fees.