False advertising, bad service

in 2019 December, I upgraded my contract with Vodacom online. the package came with the accessory voucher for R250. in order for me to access or redeem the voucher I had to go to "Vodacom.celcom.co.za”, which always displayed "error the IMEI" is not on available on Vodacom (although the phone was taken with Vodacom. I contacted Vodacom several times an on the 18th I sent a complain through their complain email add with a ticket number generated #56094, they kept on closing the ticket claiming the matter was resolved. I visited their Cresta shop, Heidelberg shop, called their upgrade department and even went to their shop in Baywest Mall in Port Elizabeth (which all of them could not assist always telling me this can only be taken with their online depart who had already failed me thousand times). Today 25th March after I again follow up this query I get told "The accessory voucher was part of the Summer campaign that ended on the 6th of January but was later extended to the last day of February 2020. The customer in question received his order on the 7th of Jan 2020". which is a pure lie, how can a December order only arrive in January "says a lot about their service".

I have been a loyal customer with this company for years now and I have not missed a single payment with them yet they can treat me like trash and worst of all lie about their facts, I am cancelling my contracts (four) with this foolish company