Complaint Review: toyota financial services

Toyota Financial Services liars and rip off to customers with current payments they lie and steal from their customers.
I have always made my payments to Toyota Financial Services.  I have been given the run around for over a month now about a payment that I made at a payment center that it came from the wrong account on 8/15/2012.  In 2/27/2013 they called me asking for proof of the payment because I was now behind on my payments.  It took them 6 months to catch this mistake on their part.  I provided them with proof of payment and the fact that all statements show that I have no past due amounts. 
I was promised a call from management to resolve this issue that never came.  I got a collection call on 4/3/2013 stating I was 30 days behind, and that it started on 8/15/2013 now I have proof of that payment they changed the story.  Telling me that they got a call stating that my payment for May of 2012 came from the wrong bank account and that the owner of the account filed a dispute with them, but did not file charges??? If someone takes money from me I will file charges?? They cant provide me with the name of person, nor give me information to the investigator.  I also made the payment in May from a payment center.  I get a different story every time I call and never the same person.  I have had it with them.  They lie and steal from people and give us the run around when we want answers.  They are also rude and will not admit to their mistakes. I can never get a member of management they are always unavailable.   
Toyota Financial is the biggest nightmare I have ever faced.  They want me to provide proof of payment that I made causing me hours of research only to get a different answer once I provide proof.  I think it is time to file a lawsuit.