Quoted from roc-noc:Learn to fix them yourself and not depend on others to repair and maintain your pins.
Cannot agree more with this, and not just applying it to pins - you want it done right, learn to do it yourself.
Either way though, if you were charged $300 for that service, you bet your ass the guy doing the 'servicing' should come back and make it right (honestly, how long did he actually check out the machine? An hour and a half, max?... damn, for $200/hr I'll 'fix' any pin too); if he doesn't, it sucks and lesson learned... but seriously, if it doesn't work out to where the 'tech' comes back free-of-charge, take it on the chin and use that as motivation to learn how to fix your own pins and not rely on some CL pin repair all-star who may, or may not, stink of cheese and/or unwashed BO to make your pins bullet-proof (even though pins break all the time, paying some jack-off $300 to do it is crazy unless you literally have no time at all to learn/ask how pins work... but if you have time to play pins, you have time to collectively learn how fix them).
The best ally you have is Pinside/RGP, there are so many good people and knowledge here (and RGP) that if you start a thread and it's still not fixed, it cannot be fixed.