FaceTime for Mac purchased from the Mac App Store includes complimentary support for the first 90 days of product ownership. After that time, support coverage is based on the Apple hardware product on which you are using FaceTime for Mac. Depending on your product's coverage, you may need to pay for support.
FaceTime for Mac bundled with a Mac purchase
Coverage for FaceTime for Mac that comes with the purchase of a Mac is based on that Mac's coverage status. Telephone support is free during your hardware product's complimentary support period or with an AppleCare Protection Plan. Depending on your product's coverage, you may need to pay for support.