Product: Credit card or prepaid card

I had XXXX XXXX XXXX on my Wells Fargo credit card, XXXX XXXX upfront fee and XXXX no interest charges. During that time I accidentally overdrawn my checking account and the overdraft protection covered it. Called customer service and paid off overdraft amount and interest charge for XXXX months on overdraft. 
However, Wells Fargo applied my payment to XXXX of the XXXX XXXX and the overdraft remained at XXXX XXXX interest charge. That was in XXXX of XXXX, and there have been at least XXXX different people involved with my case at Wells Fargo 's `` XXXX XXXX XXXX XXXX '' in South Dakota XXXX XXXX different officers filed complaints on my behalf at my local Wells Fargo Office XXXX 
Twice interest charges several XXXX dollars were reversed, but the problem not fixed and the interest charges continued. 
At XXXX point I received a letter stating that the " Overdraft '' amount was transferred to " Purchases '' with XXXX XXXX interest expiring XX/XX/XXXX, which was the correct date for the XXXX XXXX into which my overdraft payment was placed. I found this solution strange, but I assumed that for whatever reason this was the easiest way for the bank to fix the problem and what mattered was the XXXX XXXX interest. 
However, on my next statement the " Purchase '' amount was collecting XXXX XXXX interest. Due to health issues and other personal complications ( I am XXXX XXXX years old ) I didn't immediately take up the fight - calling Wells Fargo was a time consuming stressful and frustrating exercise. Dealing always with a different person at the Complaints Management Office who didn't return calls, sent computer generated e-mails and always informed me that they will contacting me eventually. 
In XXXX I started another complaint through my local branch but there was no resolution before the Promotional Advance became due, so I made another call in which I called Wells Fargo 's actions " criminally incompetent '' and that brought a XXXX XXXX from the Arizona " XXXX XXXX XXXX '' on line who was very sympathetic at first and was going to transfer my call to a " Finance Group '' that was supposed to be able to fix the problem. 
When he came back on the line, he informed me that the " Finance Group '' was not available and Wells Fargo has a policy of applying payment to the outstanding balance with the lowest interest rate, in my case that was the Promotional Advance with no interest, just the upfront fee which I had already paid. He also advised me to pay the amount that was due on the XXXX of XXXX but not the amount under " Purchases '', which actually should have been in the XXXX XXXX and not collecting any interest. He also told me to await the outcome of the latest complaint with the XXXX XXXX XXXX. 
Finally I received XXXX letters from XXXX different people at that office which are simply non-sensical and completely misstate the facts.They informed me that my problem has been resolved and no more interest adjustments will be made. At this point I have been charged again almost XXXX XXXX dollars. 
Concerned that I will not be able to get justice and relief, I have decided to pay off the amount under " Purchases '' and just forget the whole thing. Called Customer Service wanting to make sure that I am paying the right amount to the right place and this time I was informed by that agent that I can not decide where my payment goes, that's the bank 's decision, and if I want to avoid the XXXX XXXX  +- interest rate charges I had to pay off both Promotional Advances - the one that was due in XXXX and also the one that will be due in XXXX of XXXX. And, of course the XXXX XXXX upfront fee was already paid on that one also. 
This is a complicated and convoluted case but I have all the e-mails, letters and of course the monthly statements, as well as the dates and names of some of the XXXX XXXX people not with the South Dakota XXXX with whom I talked. The XXXX XXXX makes the situation much easier to understand and it does underline the fact that this could have and should have been resolved in XXXX minutes in XXXX of XXXX Several issues I'd like to point out : most important is the fact that the bank had a contract with me about the XXXX XXXX  that should have absolutely no connection to the overdraft protection. 
I can not recall any place where this convoluted relationship between the XXXX XXXX and overdraft protection was explained and/or brought to my attention in such a way that it was clearly understandable. 
Furthermore, it is obvious that their own Customer Service people have no idea of this convoluted relationship between overdraft protection and XXXX Balances. 
They twice reversed interest charges, sent me the letter promising the resolution with the XXXX XXXX  interest and no one until XXXX XXXX in XXXX of XXXX told me that the bank has this policy of depriving me of my right to decide how and when I pay off my debt, so they can charge these exorbitant fees between XXXX and XXXX XXXX 

If this practice is indeed legal, it is most certainly unethical, immoral and should be illegal. Regardless, Wells Fargo 's handling this situation for more than XXXX months is so negligent and incompetent that is hard to believe that they care about anything but profits. What happens to the customer is completely irrelevant. 
Finally, I would like to ask for a resolution since I need to know if I indeed am required to pay off the Promotional Advance- not due until XX/XX/XXXX - in order to avoid further interest charges. Also, I would like the interest charges since XXXX reversed. 
Thank you for your consideration, and hopefully quick resolution of this matter, with Best Regards, XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX Ca. XXXX XXXX