Premature cancellation/Unauthorized Insurance

Good day

I recently bought a laptop with you this month will be my third debit order of the device, the laptop was bought on contract lenovo at blu valley mall centurion, I have spoken to a lady (Sharon)that was assisting me and handed over the laptop the begining of the month of April (17th)she then said I should take it to repair centre which I refused because I bought the laptop at blu valley meaning in actual common sense I should bring it back to the store where I bought it. She took time and never gave me feedback, I have to be the one doing follow up which I find it very unprofessional as her after service is bad till this day no feedback provided. I then request to cancel my contract with she (Sharon M)was quick to provide the number that needs to be dailed for cancelation spoke to a guy who then said he can't assist with cancelation of the contract, the store manager has to cancel and do a store escalation. I cant be going up and down and still make payments of a device that does not work at all. I want to cancel my contract and not willing to pay any premature Cancellation fee,the store must be liable, yesterday I went to do follow up on why my debit order bounced when I had enough money only to find out that she only added the insurance to cover the laptop last month after I have complained,I was told upon taking the contract that my device was insured which I agreed to paying,on the 27thMay I see unpaid debit order.when I asked her she said it's probably the insurance. What kind of service is that increase premium to do damage control.surely that means I must pay unplanned money which I can't afford.can someone take accountability please.