Consultants mistake on the Vodacom contract made us pay without receiving the benefits

The consultant wrote the wrong number for my contract and when I went to complain several times they did not recognise that the number on the contract was incorrect. I have been paying a contract I have not been getting the benefits of for 2 years now. When I went to a different branch they were able to pick up that the number on the contract was not the same number on the sim. They are claiming that we took to long to report the problem and that there is nothing they can do even though we were paying for 2 years and the mistake was made on their part . They were not able to fix mistake when we went to complain about not getting the benefits