Un experienced and rude

Just had a call again from the contract department. This is the 100th call from them. My contract with them is almost over and now they keep on calling and asking to renew the contract. After I told the guy that I don't think I will renew the contract he keeps going on and on yes but why not. I told him at this stage it doesn't make financial sense to renew the contract after and told him I will just use pre-paid. After that he laught at me and asked me Do I know how expensive that is. This is not the first time and then wail I am still talking to him he just drops the call. This is the most un professional place and people that I have ever come in contact with. Just over all bad experience with Cell C