Who is not doing their work

<p>We have changed from MTN to Cell C in March 2016. Paid the account over R7000 to clear accountin March 2016. MTN is sending us sms to say that we have failed to pay the accound,I have phoned them spoken to George the supervisor he said just mail the the prove of payment so that we can reallocate your money so I did. Then another sms with the same words and another and after 20 sms I phoned again this time it was on a saturday and George was not there so I spoke to the person in his place day he said YOU DID NOT CANCEL YOUR ACCOUNT I ask how is it that I could have gone over to Cell C if MTN did agree that I can,he said send me the the prove that MTN agree so I did and up untill now this is not cleared.All I want to know is how long is this going to go on the amount they say I failed to pay is the amount I paid in March 2016 at 1 of there own shops.Please is there some one who can clear this for me.</p>