Unhappy with lack of customer service from Cell C

i was sold a product over the phone by Cell C - extra data for R80 per month per sim card - upon the interaction taking place, I specifically asked if this data could be added onto my childrens current package and numbers. The answer was YES it would be. However, this is not the case. I recieved 2 new sim cards for new numbers from Cell C which does not make any sense as my children need extra data on their current package. I have spoken to 2 sales assistants over the phone one whom said they would escalate my issue which never materialised and then another whom promptly cut me off when asking to speak to a more senior person.

One cannot even go into a store to query or rectify this as the product was sold over the phone so they are unable to assist they say!

Please Cell C - give me a call back as I am wasting money each month for data that is not being used!!