UDU quick to say behind on payment, slow to answer calls and emails.

since i had this loan i never had a problem, now all of a sudden there is a problem. the debit order for my loan went off as usual on the first of December as scheduled. on December 3rd at 2:19 am i received an sms stating my loan is behind and they are charging me interest. iv send 2 emails and phoned 3 times with no answer. this is reflecting badly on my record because they haven't updated their side.