Lewis has had my faulty washing machine for 4 weeks now!

I have an account with Lewis Stores (Springs branch) which I opened in November 2017 where I took furniture worth quite a lot of money. In less than 6 months my brand new washing machine has been taken to repairs three times already. I had to stalk the store manager to get someone to fix it, which is ridiculous! I have now been without a washing machine for four weeks now, which has been a major inconvenience. I bet you if I skip a month or two not paying the account, they will stalk me with calls to pay. How on earth must I pay for a washing machine that is not in my possession. I have indicated to the manager that I no longer want that washing machine, as it is faulty. She said she will see what she can do, which is unacceptable, she must just give me a new machine, there is nothing to debate here. Perhaps I should suspend payments to the account until they give me a brand new washing machine...the service at Lewis Springs branch has been incredibly appalling and frustrating!