CELL C No support service

i received a call from the retention department of CELLC. they made me an offer to upgrade my 2 contracts for cellphone which i pay for. This upgrade happen last month approximately 25 th. Till today no one has called me upgrade. I made many calls ( x4) with no resolution till now. The customer care email does not work and the customer service department is totally unhelpful. That means not knowledgeable on how to deal with customers. expect to speak to someone that can solve a problem is what i mentioned to the last customer service agent. No help at all.

I actually want to cancel the contract due to poor and unprofessional service.