Bad credit on my account

This has vecome a serious problem, i changed my banking details with Vodacom 3 months ago. And every month on payday they deduct my install ment i have to pay but then it comes back as unpaid when i enquired about is they kewp telling me that the is inefficient funds in my acc but there isint so that meabs i have to every month go abd pat caah at a vodacom store this is a real issue as its wasting my time and every month i get promised this will be resolved. Could you now please have this problem fixed. Name: Joanne Bowes cell: ***