That "let the loctite let go" bit is so real, heat just works where force fails. I mangled a set of cups on an old Cannondale and swore off pullers for BBs after that, torch and patience every time now. Just keep the flame moving and you won't cook the aluminum.

Ugh, that is the worst. I read a thing a while back about how stores train their people to keep you there as long as it takes, because most folks will say yes just to get out the door. It's called the "time pressure" thing or something like that, and it works way too well. You feel rude walking away when someone's been talking at you for 40 minutes, so you cave. Forty minutes of pushing a phone you didn't ask for is not normal service, that's a sales pitch with a hostage situation mixed in. If the screen fix was all you wanted, I'd go back and tell them you want the old plan back or you're done, because they count on people just giving up and paying it.