MTN charges me extra charges on fixed instalment contract

<p>Last year,I app**** for a laptop contract with a fixed monthly instalment of R259 .I had not received any data from them and began to buy my own airtime to check my emails.The laptop would tell me that i could not check my emails each time my airtime got finished.As such i could not use my emails each time my airtime got finished.Last year,when i went to pay my instalment,i was told that i had to pay an extra R2000 for allegedly exceeding the data.i used my own airtime and the instalment was supposed to be fixed.Since last year,noone seems to understand my story at MTN and i have been waiting for an explanation.Please call me because noone is addressing my query</p>