New Construction AC not cooling entire home

We just moved in a 2,405 square foot home in Florida. The thermostat is set at70 but it reads 78 for most of the day. The bedroom next to the handler is freezing yet the rest of the house is hot. It’s 15 seer 2.5 ton Carrier. The h vac company that installed it came out and said it’s the heat strip. He bypassed it and said he would fix next week. Now it’s set on 70, thermostat is 72 but several rooms feel like no air st all and temp gun shows them in the 80s with air temp from vent in mid 60s. What’s really going on here? If we get another company to come out we void our warranty. I think the unit is too small

 

Having another company work on the unit will not void the warranty. The warranty is via the manufacturer, and any company can get warranty parts via a distributor for that manufacturer. The issue you will have is labor, which will not be covered.
It sounds like a duct problem your dealing with.
Equipment is not sized via square footage. A manual J needs to be done.

 

Welcome to the forums.

You'll know that was the problem when you get a monstrous electric bill next month.

If you are getting weak or no air from certain registers...... that's going to be a ductwork issue which shouldn't be too hard to figure out. Does sound like locating a new company is in order.