Product: Debt collection

I purchased a washer and dryer from Best Buy in XX/XX/XXXX. The cost of the pair was over {$1100.00}, which qualified me to receive 0 % financing for 18 months. I did n't have my Best Buy credit card with me at the time of purchase and the employee had to look it up in the system. He inadvertently ran the purchase through on my Best Buy Reward Zone Visa credit card instead of my Best Buy store card like he was instructed to. I noticed the mistake before leaving the store, and voiced my concerns because I used the Reward Zone Visa card for daily purchases and paid it off at the end of each month and did not want it to get confused with the extended financing option. He assured me it would n't be a problem, that all payments would be applied to the higher interest balance first and then any remaining monies would go towards the zero percent balance. 
I was weary, but the store was about to close and he was persistent, so we let it go and left. The washer and dryer was delivered the following week and when my credit card statement arrived, the regular balance for that month was around {$1200.00}. So I made a payment for like {$1200.00} to pay off the regular balance, and put {$50.00} towards the washer and dryer. Well, the following month when my statement came in the mail I noticed that I was charged an outrageous amount for finance fees, which should have been XXXX because I paid off my regular balance. 
Here what they did was took my payment and put it against the entire balance for the washer and dryer wiping out my zero percent interest, leaving like {$100.00} left to go towards the regular balance. 
I immediately called customer service and complained, they agreed to fix it. It took two months for the zero percent financing to be put back on, but it was n't correct. They had the wrong terms, the wrong amounts. They did n't reverse the finance fees correctly. They kept charging me finance fees. It was a complete mess. I ended up calling customer service more than 15 times in that year trying to straighten it out. I eventually just gave up and stopped using the Reward Zone card completely, I calculated exactly what the payments should have been with zero percent interest, and that is how much I paid each month. I ended up paying a little extra just to make sure they got their money, but when my husband had his XXXX in XX/XX/XXXX I had no more to give. It is not my fault that Best Buy hires incompetent employees. I have explained in detail so many times exactly what they did wrong to so many people on their end and they all said they could see it and they were going to fix it and then they did n't or they still got it wrong. The {$660.00} that they say I still owe is all just finance fees with late fees on top of finance and late fees that I do not feel I should be responsible for paying. I mean, had they put it on the store card like I asked in the first place we would n't have had this problem in the first place, but even so who in their right mind would think someone wants to pay off a XXXX balance over one that 's billing at 23 % when they send in their payment?! That 's a freaking NO BRAINER!! I was told after the zero percent balance was wiped out that I should have specified which balance I was paying off ... why would I have given up my bonus reward points to get zero percent interest if I planned on paying it off in full the next month???? That 's so stupid. Seriously? These people are complete XXXX. 

For as much XXXX as this has been, I seriously would have just paid the debt by now just to rid the stupidity from my life. That 's if I could have afforded it. Unfortunately unforeseen health issues between my husband and myself have us in a bit of a struggle and that 's not an option for us. Honestly, I take pride in paying my bills when they are my bills to pay. However, this one is not ours to pay.