I have had a car loan with mazuma for almost 3 yea...

I have had a car loan with mazuma for almost 3 years now. Within the last year they have claimed 3 times to have not received a payment from me. Every month I've sent a cashiers check from my personal bank, and the first 2 times I was able to go back and pull the cashiers checks and resend them. This time, I tracked the cashiers check and found out it was cashed 4 days after I sent the payment, and now they are calling me 2 weeks later saying they have not received my payment. I will be contacting a manager, and the BBB on Monday and filing a complaint. Absolute worst service I have EVER had with a credit union or a bank.