Cancellation of Cell Phone Contract

I renewed my dad's Cell phone Contract in May or June this year. Unfortunately my dad passed away on the 9th July 2017 and his contract is no longer needed. I phoned Vodacom and informed them that my dad had passed away and that his contract was no longer needed. They said I should send them a letter stating that my dad had passed, together with a copy of his Death Certificate and a copy of his ID, which I did. The next day I received a email from them with a Premature Cancellation form stating that I would have to pay an amount of R 46 475.03 in order to cancel the contract!!!! I think this is absolutely unacceptable and don't know what to do. Please HELP!!!!