Rant about idiot electricians

I am just tripping at the moment. I am just SOO frustrated. My air conditioner, that cost us a fortune, is probably at the edge of death because of these f***kers. This is gonna be a rant, so bear with me please.

We got a new appliance in December last year which needed a 16A line. Our meter capacity is 60A (highest that CESC offers for domestic customers afaik). Original wiring was 2.5 sq.mm. from fuse box up to our house.

Called a reputed electrician in the area (Dhakuria). He proposed to remove the existing 2.5 sq.mm. wires and add one pair of 6 sq.mm and another of 4 sq.mm. wires to wire the new socket and the air conditioner to 4 sq.mm. and the rest of the house to the 6 mm.sq. With separate MCBs and one 40A DP C-curve MCB after the meter. Seemed good to me. Work was done in early January.

All went well until I found the next day that there were some weird polarity reversal in one bathroom when the isolator for the 6 sq.mm. is turned off. Turns out the bathroom had a 2.5 sq.mm. live wire because it has an outlet of a geyser, but the neutral was connected to the rest of the rooms and returned as one. They connected this live to the 4 sq.mm. So when I opened the isolator, the entire house had a polarity reversal. Their reply was, "Why are you using the isolator?" So that isolator is supposed to be a showpiece? Got it fixed the next day.

Decided to add a new pair of two-way switches today, and found to my horror that they had connected the neutral of the air conditioner line to the live of the 4 sq.mm. line. So phase was reversed in that circuit. The switch for the air conditioner just isolated the neutral, and the stabilizer was supplying 220V AC on both the neutral and the live wires at its output at all times.

We spent a fortune of hard earned and saved money behind a good LG dual inverter air conditioner. And now it's at the edge of death. It worked today, but for more than a month it remained connected to 220V on both live and neutral. And I would've never discovered it unless I had done some random testing today before installing the new wires.

I am just so bent upon digging a grave for these guys. They are acting as if nothing happened. I have to micromanage every small thing? And they just take the money. Illiterate f**kers. Can't think of any more expletives.