Lg washing machine - Damage door by engineer

we was reqest complaint from this number +************
originally machine problem was with door lock as by said engineer and during he change lock he used knife to open door locks intact of proper tools and he beak the door lock and chipped the door at multiple spots. when we complaint him about door locks break and chips he said i told you it can be break and he make excuses and he said we always do like that's it's normal he never except his mistake and he is argument with the topic we have cctv cameras there we can show you cctv photos how he was fixing with unprofessionally way, and before fix he said lock cost is **** and after change lock he said **** and after break door he said you have to change door your own it will cost you **** rup for whole door because of he break. i need solution for that. i hope you help me. engineer name is gurpreet. thanks