It HAS to be getting power, as he said the inside blower and outside
"unit" (compressor) are both running. They will not run without power...
most likely , or most common, problem is that the system needs freon.
Take your tester, and see if it's getting power. Note: Don't
open any cover boxes, or take off any metal panels, while
doing thing. From your post, it sounds like you aren't very
repair skilled, and there's no sense getting hurt.
Then, call your friends and neighbors. See which HVAC
service company they use, and which one has been honest in