Contract termination

My phone was due for an upgrade, I called them to do it for me as my local branch is permanently closed. The lady who assisted me said all its well and I could expect my device within 7 days, 7 days passed still there is no delivery. I called thm to make a follow up and thy told me the device tht I want in out of stock and thy not sure when will they have it. So I asked them to cancel the contract all together they kept transferring my call from pillar to post at the end. I got to retention department thy told me I hv to give a month notice to cancel a contract and I should expect a call from someone in their closure department and they will be assist me and I asked for their direct number and thy cudnt provide me with it. I am still waiting to this day and I m expected to pay for a service that I haven't received