Product: Vehicle loan or lease

My 3 year lease with Mercedes Benz Financial Services ( MBFS ) ended on XX/XX/XXXX. About one month prior to that lease end, I called MBFS to start the credit application process to purchase the vehicle with MBFS financing. I was told that a credit application needed to mailed to me and that once I received it, I could email it to XXXX. I received the credit application on XX/XX/XXXX, completed, signed, and emailed it the same day. I still have the email in my send folder. Next, I called to make sure that my credit application had been received and see what next steps were. I was told that it takes XXXX business days for the credit application to be processed and that once that happens someone would reach out to me with a credit decision. After a little more than a week, I had not heard back from MBFS and my lease end was coming up so I called to follow up on my application, I was told that a decision was still pending and that it doesn't normally take this long so a follow up would be sent to the department that makes the decision and I should hear back in a day or two form the person I was speaking to. No one called me back with in a couple of days so again I called and was given the same spill XXXX or XXXX more times prior to my lease ending on XX/XX/XXXX. In the last call, I was told that my lease needed to be extended because there wasn't enough time to process my application before lease end. I was assured by the person that I spoke to that someone would be in touch with me with a decision within a couple days again so I agreed to the extension and made an extra lease payment. For the next few weeks, I called several times because no one was calling me back and no one could seem to figure out why my application was being processed. I requested a supervisor call backs and only received one call back. I missed the supervisors call and she left a message telling me to call the general line back instead of her direct line so the issue could be resolved. I called the direct line again and could not be transferred to the supervisor. Instead, I had to request another supervisor call back. I requested on several occasions during this ordeal and only received one call back. After calling several more times, on a call on XX/XX/XXXX, or there about, I was that my signature needed to be updated on the last page of the application because it was now outdated. Not only that, I was told I needed to do another extension and make another payment ( my lease payment is $ XXXX ) to allow additional time for my credit application to processed. Again, I was assured that, by resubmitting the application with and updated date and making the extra payment to extend the lease, I would be called back within a couple of days with a decision. I emailed the updated date on the last page of the credit application on XX/XX/XXXX and still have the email in my sent box. Again, no one called me back so after a few days the call carousel started again. I kept calling. Non XXXX had answered so I requested supervisor call backs. No one called me back. Finally on, or about, XX/XX/XXXX after a couple weeks of me following up on this, I got someone on the phone, who told me that anther page on my credit application, the next to last page, also needed to have the date update from the original date of XX/XX/XXXX so I got that page updated and emailed back over on XX/XX/XXXX. No one called me so after a few days, I called and was told that my credit application had been approved and someone would reach out to me in a few days to go over the details. After a few more days around the XXXX of XXXX, no one reached out to me so I called back. I spoke to someone who again told me that I was approved and that the interest rate I received was 7.14 % and that needed to know the term I wanted. I let her know I wanted 5 years. She said that for XXXX year financing the rate would be the same and my payment would be around $ XXXX ( almost {$200.00} less than what I was paying for the lease. I was happy about that. She said that my lease was automatically extended until XX/XX/XXXX with my purchase payments beginning on XXXX, XXXX, XXXX. This would allow time for my the paperwork and terms to be finalized, I was not happy about making addition lease payments that were not going toward the purchase finance, especially since things had already been delayed due to MBFS not promptly processing my initial credit application so I asked for a supervisor call back on this issue. No one ever called me back so called back a couple more times asking for a supervisor call back each time and no one called me back. Then, on XX/XX/XXXX, since I had not heard back from. supervisor I sent an email complaining to the MBFS customer service email. On XX/XX/XXXX, I received an email back saying they could not help and that I needed to call the same number that I had been calling since XXXXXXXX XXXX XXXX  and getting virtually no where. I felt pretty defeated about making more lease payments but I at least knew I had been approved for financing starting in XXXX and my payment would go down. I did not hear anything from MBFS the rest of XXXX nor did I receive any paperwork. In XXXX I received a couple generic emails saying my lease end option was confirmed and to reach out ro MBFS. Today, XX/XX/XXXX, I reached out to MBFS and was told that I needed to go to the dealership to get financing to purchase my vehicle because someone, that no longer works at XXXX dropped the ball on finalizing my purchase. I was also told that I could not be helped over the phone anymore because I had been given XXXX extensions to my lease and they were not allowed to provide anymore. I can not even begin to describe how frustrating it was to hear that so again I asked for a supervisor call back but I am sure they will not call me back. It takes XXXX minutes to get to the closet dealership with good traffic which is why I tried to do this over the phone. I did everything MBFS asked me to do in good faith, they approved me for financing, and now, 4 months after starting the process, I need to drive nearly an hour out of my way to start the credit application process all over again. Not only that, I made {$4600.00} in additional payments that I never wanted to make and that are not being applied toward the financing that they ultimately approved me for. I have excellent credit and income so I did not have any doubt of my approval. It is just hard to believe that it took so long to get approved and then after being approved being told the I need to start all over at a dealership.