ToxicBunny
Oi! Leave me out of this...
It would be theft if the OP didn't know the company or never done business with them.
Since he knows the company and did business with them it's not a criminal matter but a civil matter as the OP provided them with debit order authorisation.
If the OP has exhausted all lengths to get the double debit reversed and its not being reveresed then its a criminal matter.. whether its theft or fraud is possibly up for debate, but its still a criminal matter.