Duplicate Debit orders

In December 14 Altech failed to run their debit orders correctly and my payment was not taken off. After repeatedly calling them they eventually took off the debit order in early January. Then then proceeded to take the same debit order off again at the end of January. They have failed to refund this over payment back to me after 3 weeks. Whats concerning is that this over payment is not reflecting on the next statement. I do not trust them with my banking details and will be cancelling my debit orders and my contract.