urban clap company - TV repair from Urban clap

On **th July ****, our tv display suddenly turned to black screen but sound was working..the issue was due to backlight..we registered in urban clap, for the technician to just visit home, they charged ***RS and the technician came home he told us the issue is because of a single strip but if only that strip is changed, again the problem will reoccur in a month..and he asked us to replace * strips each worth ***Rs so that we will get a brighter display like a new TV and will for sure last for * years..and we agreed and transferred RS ****. Then he took the TV and brought it back next day, but our display was turned blurred and was not like before and again within * hours the display went black the same issue..we called the person who repaired, he came the next day and took the tv and again after a day he brought it back, again when we switched on the display was even worse and within an hour the display went off completely..we gave complaint in the app that the problem has reoccured..now they have assigned the same person ..but we won't trust them because they are making the issue worser by using damaged product..now we want a refund of ****rs asap. Please help..there is no way to contact them for us..we tried a lot but they aren't calling us.