Incorrect phone Delivered and no response

I purchased a cellphone through one of their agents. upon receipt of the phone on Monday 15th February 2016 it was far from what I had been advised and the completely the wrong colour. Their contract stipulates that cancellation can be done within 5 business days. I phoned and spoke to a lady on the same afternoon of delivery who refused to cancel and collect their phone. Later in the day I phoned and spoke to Sherwin who advised they would listen to the recorded conversation and then advise. I then sent an email on the 16th February 2016 requesting cancellation. Still to date I have had no acknowledgement of my email or cancellation. I have not utilized the phone or activated the sim. I need the contract to be cancelled immediately and the phone collected and this is proving to be a mammoth task.