Can't cancel my contract

<p>Went to a store to give notice of 24 month contract cancellation that ends in January 2017. Shop gave me the number for retentions department and said they can't cancel in store. Been trying endlessly to get through to this number ********** . hang on for 15 minutes at a time without luck, also tried 082111</p> <p> </p> <p>I trust that Vodacom will contact me in this regard seeing that it is near impossible to get hold of them</p>