Unresponsive and seemingly unwilling to help

I recently bought a car from WeBuyCars, but after having it for less than 2months, it started giving me gearbox problems. After getting it looked at and being informed it's not fixable, I tried to get hold of the customer care center and after a few attempts I finally got a response. After explaining everything, they seemed to be interested to help, but now they are unresponsive. I'm well within my right to return the vehicle but seems like the support center is stalling so my 6month return window expires.