Hitachi India - Warranty Claim for PCB Complaint

Recently I have started facing problems as No Cooling with my Hitachi AC on **/**/****. Its warranty was supposed to end on **/**/****.
Below is the product details.
- AC Model: HITACHI AC SPLIT ***HEEA *.*TON
- Outdoor Serial No: IN-CSRG***HEEA-***B*****
- Indoor Serial No: OUT-ESRG***HEEA-SE***B***
- Date of Purchase: **/**/****
- Warranty Valid Till: **/**/****

PFB series of events
- **/**/****: AC stopped cooling. Issue started while under warranty.
- **/**/****: Complaint *********** raised. Technician Mr. Momin [+** **-********] visited and diagnosed faulty temperature sensor. I was told the part is not in stock, they have to place an order for it and it may take *-* days. He also mentioned that part is not covered under warranty and I have to pay the charges for that. I have agreed for the charges and asked them to place the order for the respective part.
I was supposed to go for pre planned Shimla/Manali trip from **/**/**** to **/**/****, Which was pre-planned almost a month back. I have informed the technician about the same.

- **/**/****: Received SMS: “ Your call no *********** is submitted for cancellation due to service Charges issue. If the work is not completed, please give a missed call from your registered mobile number to **********. TEAM HITACHI”
So they tried to close my complaint without even contacting me. However when I have seen that msg I immediately gave a missed call to dedicated number to get the case reopened.

- **/**/****: Received another SMS: “ Your call no *********** is submitted for cancellation due to late appointment. If the work is not completed, please give a missed call from your registered mobile number to **********. TEAM HITACHI”
I missed the message this time as I was travelling and couldn’t call to respective number to keep the case open. So the case got closed without contacting me while I was on my pre-informed trip.
- **/**/****: after coming back from the trip I tried to contact the technician
- **/**/****: technician replaced the temperature sensor and I have made the payment for ₹**** for the part but The AC stopped cooling again in the evening on the same day and same issue started occurring again.
- **/**/****: Raised Complaint *********** for the same “no cooling” issue, still unresolved.
- Current Status: I am now told the outdoor PCB is faulty with estimated cost of ₹**,*** - ₹**,***.