Vodacom Upgrade

I contacted Vodacom to actually cancel one of my contracts. I received a quote to go on a cheaper package. I signed and accepted the quote a day later. Two months later the sim card is permanently blocked, no voucher and now data. I have contacted them via email twice,but no feedback received. When going into the store the staff can't assist you just tells you they do the upgrade through different companies and you must email them,where you do not receive any answers.