I would do the same. If you’re not confident to do it by yourself - with the help of somebody of course, I will have it installed by someone else. If we’re talking about a possible occurrence of a dead pixel by just wall hanging it, I’ll just removed it there and put it on its stand and place it elsewhere. Then call the service.
If you’re claiming warranty just by dead pixel, sobrang dami lang din nilang reason why it developed such thing. Same sakit ng ulo, abala whether they’re the one who does it or not. Madaming pwedeng maging lapses and loop hole when it comes sa consumer rights/law natin. So if I were you, if you can’t haggle down the installation fee, save your 7k. Just tell them, you’re not goint to wall mount it - mahal pala eh. And try to ask one more time from another branch, like what Moks007 said, if its true that they can install for 3,500. No harm in trying to ask... again.
But since you bought a 190k TV, yeah... what’s 7k to that?
Enjoy and congratulations sir!