EXTREMELY HIGH BILLING ON MTN ACCOUNT

Dear MTN, This month my account was billed to the amount of R4102,79 This includes my number *** plus my wife's number she is on *** plus out internet toggle. We have not received and account stating the detailed calls. Neither are we able to log onto the website to log onto the account. This amount is exuberantly high as we normally pay a maximum of R2500 per month. Even more unusual is that we have had a had an amount of about R7000 in airtime that was accumulated on my account for which I was able to call. This was said to us by the MTN shop in Middelburg (Wonderpark). Now the big question here is where we in fact over billed and what is the detailed account. Can you please go onto our account and please check the specifics as we think that we may have been over billed. Refusing to do so will lead to us having to close the account and this is not goods for MTN nor for us. Thus the big issue here is that we have been billed this extreme amount and we do not know why. I am on on a contract where I pay R1200 and my wife pays on a top up 200 about R650 per month now the toggle can't be that expensive as it is 500MB and the sum does not make sense. Please help?