Misselling

During the middle of January I had to buy a new phone on contract and I queried whether it included a flight centre voucher (number of specials being run) and was told I would receive an sms with the details within 7 days. When I queried this with the store I was told that the promotion had ended prior to me purchasing the contract! This is misselling and I specficially queried this from the store and purchased the contract with the understanding that it would include the voucher - I have escalated this to someone at the store, the store manager and Vodacom Facebook page (was told by Vodacom to contact the store!!!!). To date no one at the store has bothered to respond to my query.