3 months of waiting for Repairs and still Nothing!

Hi I purchased a 50inch Hisense Tv and after a few Months I started having trouble with sound on my Tv. so I went to the retail store and logged a call. after a few weeks I have still not heard anything so I contacted the retailer and asked what is happening, so they advised me my call was closed and they are not sure why? So I again asked them to log a new call after 2 days they phone me up and ask me to bring in the tv to send away for Repairs which can take up to 21 working days....so I advised them that i Had the tv delivered to my home and I have no way of bringing the tv to them and as stated in my Hisense Warranty 50inch and up is Onsite repairs. but after another 3 weeks gone by I still had no feedback what so ever! Then I phoned again and asked what is happening...They advised me Hisense sent a Courier to the shop to pick up my Tv and it wasn't there? so again I spoke to a Guy from Hisense and asked if I can bring the tv to the retailer as the can not fix it onsite as they have no repair centre here. but after a few days they picked up the tv and ordered a part which took 8 working days and part was broken and now my tv is still not fixed after almost 3 months!!!