Hisense fridge not working from day one and serviceman incometence.

So I bought this Hisense fridge online from Game. The fridge did not cool from day one. I have had it from Aug 21. Finally today a serviceman came to repair it. He let the gas out and started heating the filter dryer until it started glowing. I asked him what he was doing and he said he was burning the oil out of the filter. I told him that he now destroyed the filter and that he should replace it. He ignored me so I asked for his employers' contact number. In the meantime he started the fridge. I called his employer and explained my concern. The employer then called the serviceman and instructed him to fit a new filter. The serviceman then left and said he was going to purhase a new filter. He never returrned and left the fridge running. I switched it off. He left a mess and did not move the fridge back to the position he found it. I do not feel comfortable that Hisense is sending untrained repairmen to work on my new fridge which I feel could now have permanent damge.