Product: Debt collection

Back in XX/XX/XXXX my daughter needed some XXXXl services. I applied for a XXXX  XXXX   Care Credit and the credit card was granted on XX/XX/XXXX, so I paid my child XXXXl   service with the new XXXX  XXXX  Care Credit card. 
The first payment was scheduled on XX/XX/XXXX,  unfortunately I did not receive a bill with the payment phone number or the payment address to send a payment, so almost at the end of the month decided to call and ask the best way to process my first payment, the XXXX XXXX Care Credit representative told me that I needed the account number to make the payment, number that in the time of the call I unknown, for their security reason she couldnt gave me the account number, so the best was XXXX   XXXX  send me the bill to my mailing address and then process the payment. Until XX/XX/XXXX I received my first bill from XXXX XXXX  Care Credit, it was the XX/XX/XXXX bill with the payment information, STETEMENT WITH CLOSING DATE OF XX/XX/XXXX,  PAYMENT DUE DATE of XX/XX/XXXX, and a MINIMUM PAYMENT DUE OF {$190.00} Dollars. 
On XX/XX/XXXX I paid {$100.00} dollars to XXXX XXXX Care Credit over the phone, and in XX/XX/XXXX I paid another {$100.00} dollars online, so the minimum payment was covered before the due date. 
Come XX/XX/XXXX, I tried to process the monthly payment over the phone, XXXX   XXXX Care Credit refused to accept my payment because they had the suspicion that I applied for bankruptcy, I informed to the representative that it was not the case and I will continue with my payments in time before the due date, the representative refused to accept the payment. In a second call before the XXXX payment due date I called to the XXXX  XXXX Care Credit to check if they cleared the information and if I could process my payment, again the representative refused to accept the payment and this time I was informed the account was sent to the collection department, even when my previous payments were paid in time and I was trying to pay the third month. I tried to get the recovery or collection department phone number to stop the collection work, but the representatives told me I cant contact or make a payment because they were updating the account to the collection department and they will contact to me, I told several times to the representative that I was in the position to continue with regular payments and continue with the original credit card agreement, but they refused to give me a solution to stop the collection process. After several calls I gave up making my XX/XX/XXXX payment because the continually refused to accept it. 
Months went by and never did we receive another phone call or notice or some documentations or letter in regards this debt. 
The XXXX XXXX Care Credit sold my account to a collection agency named XXXX XXXXXXXX XXXX XXXX. XXXX XXXX hired a Law Office to collect this debt, on XX/XX/XXXX they sent me a paper work of the account and I discovered the details that make this illegal collection. 
Originally the payment schedule was : 1rst minimum payment of {$98.00} before XX/XX/XXXX 2nd minimum payment of {$98.00} before XX/XX/XXXX 3rd minimum payment of {$98.00} before XX/XX/XXXX. And continuing every XXXX  of the month until the balance be paid in full. 
But as I said the first bill was lost in the mail or just XXXX XXXX Care Credit never sent out, So the 1rst payment was paid on XX/XX/XXXX over the phone, the second payment was paid on XX/XX/XXXX, On XX/XX/XXXX the first and the second payment were covered before the second payment due date. On the third payment it was not possible to process because on XX/XX/XXXX2016 XXXX  XXXX/Care Credit sold the account to the collection agency XXXX XXXX XXXX XXXX, even before the third payment due date -remember the due date is the XXXX of each month-, that should be the real reason why the did not accept my payment because they sold the account to a collection agency before the account was a charge-off, but the account was not a charge off because I paid the first and the second minimum payments before the due date of the second payment. XXXX  XXXX/Care Credit excused in I was applied for a bankruptcy but that is a lie, the true is they sold an account to a debt buyer before the account was a charge off. 
Now XXXX XXXX XXXX XXXX ( debt buyer ) hired a law office -XXXX XXXX XXXX- the law office is attempting to suit me for this debt, a debt the I never refused to pay ( the original creditor refuses to accept the payment ) I want to pay in the original terms stipulated with the original creditor.