CELLC are dishonest and *******

I have a contract with CellC that is paid on time every month. Earlier this year I contacted them to ask if/when I would qualify for an early upgrade. I was told early July, without any additional cost. It’s July and now the story has changed from July to September. I could only upgrade end of July if I paid them R3718,14. I don’t understand the flip flopping and change of stories especially if I am a diligently paying customer. And reaching their retentions department is almost impossible. Calls get cut off. I’m so annoyed