Complaint sub-issue: Attempted to collect wrong amount

The trouble with these " FORMS '' is that the categories are NOT complete for every type of complaint. My complaint is with the DEBT CHARGING Tactics and DEBT Collection Tactics of Discover. 
This is NOT the first time this has happened and I am not convinced that it is accidental. I believe it is willful and an attempt to defraud ( mail fraud, wire, fraud, theft by deception-take your pick ). Discover will call if a payment has not been made on the exact date of the due date ( even if I paid in advance ). With these phone calls, they pressure to PAY in advance. I paid a payment of {$120.00} on XX/XX/XXXX ( online ). They phoned me two days later to complain that the payment amount was {$18.00} less than the minimum and that it was now late. So to avoid late charges, they wanted both the {$18.00} and the XX/XX/XXXX payment. I do n't remember agreeing to such transaction. However Discover states that I agreed and set up a future e-payment for XX/XX/XXXX. Now on today, XX/XX/XXXX, Discover called me to tell me that I was NOW late for the XX/XX/XXXX payment and that the " future '' payment that we set up XX/XX/XXXX had been returned. Ordinarily I would not have questioned this tactic because I thought Discover was a reputable company. However I knew there was some deception in that statement because I have money in the bank ( never a XXXX balance ) and I have " overdraft '' protection. So If any payment had been processed it would NOT have been returned by my bank as the Discover Agent was alledging. So to " correct this matter '', he attempted to collect the past due payment, late fees, returned check fees, and the XX/XX/XXXX payment. I explained that because there would have been NO REASON for my bank to return a payment, I refused to pay over the phone. I stated that I would rather investigate the matter and handle the payment after I have done a proper investigation. He then proceeded to tell me that they had a program to " reduce '' interest payments for 6 months or 12 months if I would just pay the {$260.00} amount Over the Phone today. -- -- - I did not trust Discover to get it right. I did n't understand how a " program '' to reduce interest rates could just arbirtrarily be reduced for 6 or 12 months at their discretion without some other condition. He explained that If I chose the 6 month program that interest would not be charged and neither could I use my card for future purchases for 6 months. Second complaint, I have NOTA made any " purchases '' with discover in over 12 months. My balance is primarily due to Transfer of other credit card balances to Discover and the Interest rate was supposed to be 5.9 % or less. Then I checked my statement and saw that I was being charged approximately 19 % interest for over $ XXXX in purchases. As I stated, I have not made any " purchases. '' -- - I believe their collection tactics are unethical. I believe their charging of EXCESSIVE interest is immoral. I also know that the recent fees of {$35.00} ( late ) and {$25.00} ( returned check ) is completely illegal as it is FRAUD. My bank statement is enclosed to show that there was NO Returned check at any time from XX/XX/XXXX through XX/XX/XXXX. The Discover represented admitted to me that they had made an " error '' in processing the payment for XX/XX/XXXX which they claimed we set up over the phone when I made the payment of {$18.00}. He claimed that they entered my account information incorrectly and it was NEVER processed to the bank. This is not the first time Discover has used this tactic and charged me for their ERROR. I want my fees for late fee and returned checks credited to my account. I want my interest rate reduced. I believe Discover has deliberately and fraudlently charged me for interest and fees that were in error and as a result guilty of usery.