Answers

You'll probably have to arrange a time to have someone meet them during their working hours 

I know it's not convenient, but you have to be somewhat flexible when it comes to meeting repair companies at your home. It would be easier to have them commit to an early appt. rather than at the end of the day. Other appts can throw the day off. Also keep in mind, if someone comes to your house at 7pm and has already been working for 10-12 hours, they're not going to be at there best. The same is true on weekend. After putting in a 50-60 hour week, you are drained and need to relax and gas back up.

Contact the HVAC manufacture i.e. Goodman, carrier...ect also and notify them to iniaite a warraty log and ask them for assistance. If you have a NEW HOME book from the builder it should list the HVAC Install company of the HVAC Sysyem. Be Professioanl and Persistant. No Builder is perfect and most importantly try and notify the leadership of the company. Be flexable and cooridinate within the schedule set by the warranty ENSURE YOUR HVAC SYSTEM IS REGISTERED IN YOUR NAME AS IT MAY EXTEND COVERAGE