Product: Vehicle loan or lease

I purchased a XXXX XXXX on XX/XX/XXXX, financed through GM financial, and over the last 6 months I don't believe my payments have been applied or calculated correctly. I have been requesting my account balance and interest payments be corrected since XX/XX/XXXX but have received little to no explanation or resolution. 

I have been paying extra on my auto loan in an effort to pay down the balance faster with the expectation that anything above the {$750.00} due, goes towards the principle and not the following month 's payment. 

There was some confusion in XX/XX/XXXX as the GM Financial app and my XX/XX/XXXX statement showed {$0.00} due on XX/XX/XXXX. Because of this, no payment was made specifically for XX/XX/XXXX ( a payment was attempted XX/XX/XXXX but cancelled ). After a phone call with customer service explaining my intentions to pay extra each month, they corrected my XX/XX/XXXX payment. My GM Financial app then showed a balance of {$1500.00} ( {$750.00} for XX/XX/XXXX and {$750.00} for XX/XX/XXXX ). This payment was made, as noted in my payment history. 

I made another {$5000.00} payment in XX/XX/XXXX. After noticing the additional payment was being applied to XXXX and calling customer service again, the XXXX payment was corrected. 

I made {$1000.00} payments in XX/XX/XXXX and in XX/XX/XXXX. I then noticed on XX/XX/XXXX that my GM Financial app showed a past due balance. I called customer service again and was informed they would perform an " account research '' to determine why I had a past due balance. 

By XX/XX/XXXX I had not been contacted about the account research so I called again. They were unable to give any further info on the account research but did inform me that my XX/XX/XXXX payment was reversed which is why my account was showing a past due balance. I reviewed my bank statements and no money was refunded to my account, from GM Financial, in XX/XX/XXXX, or any time prior. 

On XX/XX/XXXX I called customer service again. I was informed the account research was approved and still open but nothing further had been documented. I was also told that the past due balance was stemming back to my " missed '' payment in XX/XX/XXXX and that each payment following ( XXXX, XXXX, XXXX, and XXXX ) had been partially applied to the current month and partially applied to the previous month to cover the past due balances. My GM Financial app and my account statements did not show a past due balance until the end of XX/XX/XXXX. 

I have made a payment for every month greater than or equal to the balance due, therefore I should not have any past due balance. After reviewing the transaction history, I have additional concerns about the amount of interest that was charged for the first 3 months, and why my XXXX payment was applied to XX/XX/XXXX. As noted above, I have called customer service several times but they have been unable to provide an explanation or resolution to the issues I have described. I sent an email requesting an explanation to the above issues XX/XX/XXXX and received a generic 'Please contact customer service ' message. When I called customer service, they again could provide no explanation, resolution, or info on account research in progress. I followed up this most recent phone call with another email on XX/XX/XXXX and have not received a response.