Please upgrade my Data Bundle

Telkom tele-sales contacted me in Marsch 2015 and offered me an upgrade of my existing telephone service and my current data package which was 5gigs per month at the given time. They then sent me another modem and various extras (which I dont need or want) and guaranteed me faster line speed and a 20gig soft cap bundle. Since then I have spoken to various operators and floor managers at telephone 10210 explaining that I would like a 50 gig bundle as I was not happy with 20gigs. I contacted our local Telkom cellphone shop in Shelly centre, they tried, but in vain. Every time they gave me a ref. number and promised that within 7 days the service would be updated, then I get told the system does not want to \migrate"from one package to another. Telkom is in breach of our contract by not being able to supply me with the guaranteed line speed. Their opposition"