Concerned contract customer

So I bought a home router online as advertised and on the package it stated that I will receive 200gb for an amount for R400 monthly which I only receive 30gb yet the still deduct even way more than we agreed on they deduct R536 instead. I called the helpline 3 times refs the matter and they all tell me the same story my matter has been escalated to the billing department till today and it’s only been my 2nd month with this contract. Hello Peter kindly help me with this matter