OBF- Faulty Phone

I took out a contract with Cell C and took a Lumia handset with in day 3 after I have took out a contract the phone rebooted itself on countless times a day and that as a results I went back to the store and returned the phone and opted for a different brand I told them to cancel the current Lumia contract and then re apply for a new contract with a different phone <br> <br> They are forcing me to take the same phone of which I declined I cannot take the same Lumia brand regardless whether its new or repaired I am no longer interested in Lumia brand because already I had bad experience within the first days with the phone , so I told them I want a different phone they must cancel the current contract and re apply again for a different phone , they refuse to assist me they said I must pay R3000.00 the cancellation fee, How Can I pay that ridiculous amount for something that was faulty I have a right to get a different brand. <br> <br> This is very bad service and poor communication from Cell C , how can I pay that money if the phone was faulty , and as a customer I have a right to get another brand , I am very angry with the outcome of the service with Cell C How long must I wait to get help .