Bad customer service

My contract was due for an upgrade, so I went to MTN Eastgate for my upgrade. The phones that I wanted were on a different package and I was made aware that my packages needed to change for me to have that handsets, granted. So I gave Dikeledi strict instructions that, I wanted to still be able to load airtime and data onto the phone should I run out of minutes or data,she promised me that would be the case. Now to my surprise I received two tax invoices saying that I owe MTN R2400 and odd rands on my account of which apparently it was used up by data on both my contracts, baring in my that I kept loading airtime and data on my phone. So I decided to contact 808 to find out why they billed me so much on a top up packages? That's when the consultant told me that I have an open line of which I knew nothing about, to top it all the other handset I hardly use but it's the one with the highest bill. The I decided to go to the Eastgate store to query this matter , I was assisted by this other guy who logged a complaint for me and I was given a ref number and a turn around time, I was expecting a call from MTN BY MONDAY ALREADY never got back to me till this day. MTN is BAD I won't pay.