Switching networks

I have a contract with vodacom for only airtime and data (no handset). I phoned vodacom today to ask if it is possible to migrate my contract in order to get a new handset because my handset is getting a bit old. I was told that it is not possible to add a handset to my current contract and that I would have to take out an additional contract. I understand that is the way the contract is set up but it just does'nt make any sense because if I took a handset with my contract they would have made more money off me. I did a bit of research online and discovered that there are other network providers that have the same handset that I want for cheaper and with more data. So I am on my way to town now to take out a contract with another network. I would have stayed with Vodacom if they offered me a new handset but unfortunately its impossible due to the company policy. I will also now be forced to cancel my 5 vodacom contracts that I had for years when it expires in order to make save money.