WHY MUST I WAIT

I got divorced recently and my cell number is on my ex wife's name. the contract expires now 30 September 2015 and then starts on prepaid 1 Ocktober 2015. The guy at the store tells me that I cant take out a contract on the same number because I need to be on pre-paid for at least 3-6 months to see how I buy airtime. I mean you go into the store and get a contract without any previous pre-paid history and now a user on vodacom on another number that gets paid on time and even this number gets paid on time now you want to start *** like this. He says I must come in and get a new number and rica it again that is a load of **** because I need to pay for the new number and application and need to change my number on all my business cards and boards because you have ****ty rules or just a lazy guy there. I you will take all those costs then I will do it but she specifically stopped the contract because we are divorced and that I could keep the number and the same with me to stop my other contract with vodacom and let my ex stepdaughter keep her number.