Bad experience

I bought a 55inch sansui at russells in july2021 the TV went blank in December 14 i went to Russells and complained about it they told me they will tell me when the electrician's come, I have been waiting for them, when I call them they say they don't know when they are going to fix it, I'm so disappointed in their services, it seems like they don't care about their customers, I want to cancel the instalment on that TV because I don't watch it. Please help me I want to know why they don't communicate with the customers and suppliers.