[Resolved]  Voltas — 2 defective voltas ac from purchase

We recently purchased 2 spilt ac and both of them are defective.
It's so hard to believe for me, i spent so much for two defective pieces which don't even work for one day that too from such a reputed company voltas. We recently purchased the ac from the chandigarh, paras enterprise, sec 35b. Model r-410a, 1 ton and 1.5 ton and after the fitting, they just don't work. They can't do the work of cooling, which is all they supposed to do. We have registered the complaint and even call the shop, they told us they can't just replace the unit as it's opened. They failed to take any responsibility of it. Can anyone in voltas tell me if you can find the fault in ac just by looking at it in packed version and without the fitting?
Engineer came and told us sensor is not working for one and for other they didn't even able to find the fault. If i am spending a fortune just for defective boxes then i like to have a refund please as you can't provide a replacement. Repair is not an option here, i am very disappointed and like to have this issue address at the earliest please.