I have been paying my auto loan for over two years and have actually overpaid each month, sometimes paying more than twice the minimum amount. Out of nowhere four months ago I was contacted claiming that for two and a half years, without notice my due date was earlier in the month and despite overpaying I had accrued years of late fees. I was assured that the late fees would be cleared and the due date changed. A month later after " solving '' the problem I was called over ten times in one day for the same issue. Another month later after " solving '' the problem again I was called over ten times in one day and had to " solve '' the problem again. This harassment has gone on now for four months. I have sent them a cease and desist notice and advised that if the harassment continues, I would be seeking legal action. 
