Car letter on the way to the bank lost

Hello, I’m new here and I need your advice. The following has happened. We got a new car in October 2017 that runs through financing. The car letter was sent to us so that we could register the car. At the handover in the car dealership we handed over the car letter again. (We have a confirmation for this) After several months we noticed that the bank has not booked any instalments to date. After consultation with the bank, she said that she had the In October 2018, the car dealership arrived at us and wanted to have paid the purchase price of us within a few days. We clarified to the car dealership that it was a financing and that we had also reported to the bank about what to do with the debiting. According to the car dealership, they did not have a car letter and after repeated returns, the car dealership would not have paid the car. 2 weeks later, the dealership said that the car letter was probably lost in the mail (I have to say that in October 2017, the car letter was sent to us only as a normal letter). Now we should arrange for the car letter to be offered so that we can have a letter in our hands again, or have to send it to the bank. Yes, I am aware that I have entered into a purchase contract and have to pay for it. he, which is not quite clear to me, why does a car dealership only come to mind a year later, supps there is still not paid a car? And now also muddys the car letter and we have the racing shop to apply for this new. We certainly still bear the costs. The question is now also, the financing remains or statute of limitations because it has not (yet) been used. LG Matthias