Upgrade Gone Bad-Pathetic customer service

Contacted customer service on 180 regarding data contract ***) and was told i am due for an upgrade for this data contract and the agent said all I need to take with me is my I.D so whilst on the phone checked online on data packages offered and chose the 50 gig LTE deal with Router so agent said i can choose said package as it is data . I proceeded to Telkom Mobile store in Kenilworth Centre and here i was told i cannot upgrade as I have to cancel existing data contract and reapply . This was a waste of my time as there must also be a pro-rata to be paid in , In February i app**** for an iPhone contract ***) and was told then i cannot upgrade from data to voice that's understandable so I took a new contract but this time I am totally fed up with the inconsistency of your agents and their lack of knowledge or expertise on products you market why say I am due for an upgrade from data to data when this seemingly seems like a way of binding people to contracts . I am a pioneer of Telkom mobile products and have been a good customer now my feeling is to cut off ties with Telkom Mobile and revisit other Service Providers as being a good customer I feel unfair treatment.