Product: Credit card or prepaid card

I bought a couch from XXXX XXXX XXXX on XXXX. I opened a credit card with them to take advantage of the 0 % interest, since I had done this before with them about 8 years ago with no issues. My monthly payment is {$82.00}, so I set up a weekly automatic payment through my bank for {$25.00} every Friday, with the first payment being made XXXX. Everything was going fine until I looked at my XXXX statement and saw a {$30.00} late fee on it. I used the chat feature on their website, and the agent was very nice and waived the late fee for me. I ended the chat and then was really wanting to know why I got the late fee, so I tried to start another chat, but it was late at night and no one was available, so I waited until the next day. The rep I chatted with was very nice and listened to what I had to say, but I was blown away by the reason I was charged. My due date is the XXXX every month, and so far, the statements have dropped on XXXX, XXXX, and XXXX. Well. I have paid {$25.00} every Friday, so there's no way I should be charged a late fee, right? I'm paying at least {$18.00} more than the minimum every month. So, apparently with this card, if you pay after the due date ( XXXX ), but before the statement drops ( XXXX or XXXX ), A WEEK LATER, your payment gets applied to that month and will NEVER be carried to the next month. This is what the representative told me. When I look at XXXXXXXX XXXX statement, I have payments on XXXX, XXXX, XXXX, XXXX, XXXX, and XXXX. That's {$150.00}. XXXXXXXX XXXX statement says I paid XXXX, XXXX, XXXX, and XXXX. So, according to their shady practices, I only made three payments by the due date in XXXX. They did not take my XXXX and XXXX payment and apply it to XXXX, even though I had already paid {$100.00} by the due date in XXXX, because they were made after the due date and before the statement generation. Excuse me??!! So they are essentially only giving customers three weeks to pay their bill without receiving a late fee. This can't possibly be legal. I looked at all the disclosures that are available to me and this is mentioned not one time. So now it says I owe {$110.00} for this month, because of the {$30.00} late fee, so I asked about it going back to {$82.00} since the late fee was waived. The representative told me that since the statement was already generated, they can't change it from the {$110.00}. Well, I made a payment XXXX, but guess what? That doesn't go towards XXXX, it is counted as an XXXX payment. So now, not only do I have to pay {$110.00}, but my first {$25.00} payment for this month doesn't count towards it, and now I only have three weeks to pay {$110.00} without getting charged a late fee. What am I supposed to do? I'm having to pay an extra {$55.00} this month with a week less to pay it. How is that not detrimental to me when I did NOTHING WRONG? I have been paying faithfully and over what they're asking for and this is how I am treated in return. So while they waived my late fee, I am still having to pay an extra {$30.00} this month, or I'll get another late fee! So I am forced to pay the late fee that they " waived ''. I just wonder how many other people are doing the same thing and getting charged {$30.00} late fees here and there, but they don't pay attention, so this company is just making money off of GOOD CUSTOMERS. As I have said, I've purchased from XXXX XXXX XXXX before, and I really do love the couches I've purchased, but after this situation, I will not be purchasing with them again, and I will warn everyone I can about their shady practices.