MTN billing taking more of my money then the contracts agreed on

I have 2 contracts wih you for data [internet] both hould be R299 as advertised but the amnount bills reflect more than double the amount!

This is the 3rd or 4th time that you are taking more than the agreement and i am fedup with your ****!

I want this sorted out today! I will stop all the debit orders to MTN and i will sue yu for the business i loose if you cut off my internet or cellphone services!

How can a contract for R299 become R697.95? Both of them??

Stop *****ing my money MTN!