Cell C re occurring debit order

I don't have any dealings with Cell C but it's the 2nd month they trying to debit my bank account. I tried to enquire but the 24 hrs turn around that they promised to get back to me has passed. 0n the 26th Aug amount of R199 ref Cell C SP ******8 went off my bank account. Again on the 1st Oct I was being debited with R890.38 ref Cell C SP ******8

I need to know what do you want from my account number. I also need to know of how did you get my banking details, further to that I need details of how did you obtain consent from me to debit my account. Please provide that via email so I may take it further.