Panasonic - Dishonest service

Dear Sir/Madam,
My tv had a video problem, I complaint to panasonic (my request no. R************) the service person came from nearest show room.

I thought they will sent from Panasonic but they sent local service person who’s not belonging to Panasonic.
That person told me that, we need to change the backlight and if problem in panel that also we will change for that they estimated including service charges around **** rupees. I said them ok you can take my tv for service . Thus They took my tv on last Tuesday and return on Thursday(**-**-****) but they not rectified my tv problem as they committed. I asked them clear details why you couldn’t rectified. They told me that the parts are not available. But they charged estimated amount without proper justification.
This is first time I experienced worst service from one well known company.
If they openly said to me, they can’t rectify the problem. I would have buy anew tv. But they didn’t tell that.

I asked clear justification for that bill amonunt.what they did? Why they charged that much?.they didn’t tell proper answer.
I trusted Panasonic. But as per their brand logo. Not a idea for life. It’s idea to missuse the customers.
I didn't asked them to do third party’s service but they did without my consent. They cheated me.
As they agreed that they did a failure service.
They ready to give refund but they want to make my TV as non-working condition.
This is not a good and I couldn't expected from one renowned company.
They are not not giving value for customer money and pain.

Regards,
Ramesh