Cancel contract and refund my money

This has to be the worst telecommunication company I ever had to deal with,I app**** for a contract in last year October and they delivered the wrong device,cancelled the contract within 10days,till date the device hasn’t been collected,when I call they take me from pillar to post,but monthly Money is being debited from my account,the worst customer service ever now their consultants are threatening to blacklist me for not paying since I had to close my account from being debit for a cellphone that I don’t even use!!