Bad service

I bought a Huawei nova 8i dual sim brand new with in a couple of months the motherboard of the phone give in I then send a new phone in for repairs. They repaired the phone and put it n a single sim motherboard in the phone they knew it was n dual sim and still they put in a single sim motherboard. I then logged a another repair report and they said with in 3 weeks the motherboard will be here and it has been over a month and they still can not give a date when it motherboard will be here Ravi Krishna the agent that is helping me dont like to reply on emails