unknown billing

I've been billed money that I dnt understand and every time I phone in am told to send them my bank statement to check, am very upset because my important debit order bounced because of RAIN. Can someone call me or reverse my money urgently. The 1st payment when out on the 1st of October of R250 and few minutes later am told to increase my online limit because the whole R499 payment couldn't go through which made sense cos i had to pay R449 to my surprise the next day after I've increased my limit instead of R250 deduction there's R499 deduction on top of the R250 taken the previous day. Can someone help understand this?