Completely disgusted service

Extremely annoyed and frustrated. I cancelled a sim card and paid the amount i owed them on their website. I then tried to do a upgrade that never arrived and requested it cancelled and i thankfully got my refund. Now for 2 months in a row they try to take money from my card i use for something i dont have. I have requested the stop as i am getting bank charges for unpaid debits. I only got a automated response to say they will contact me and nothing further. Again this month theu tried and again i incurred fees for unpaid debits. Then to top it off I got an sms stating they tries to debit my card again. This is frustrating as i am not getting anywhere or any help. Bad service