Master Mechanical Air Conditioning and Heating

I purchased a complete HVAC unit September 9,2017 and informed both Mario and George that the unit was not performing upstairs. They ensure me the unit would perform by replacing my old unit with 3.5 ton rather than a the old 3.0 ton. An inexperienced technician arrived to adjust the damper, however the issue was not resolved. I’ve made numerous attempts to reach them since October 2017. They are not returning my calls nor the calls of a friend that recommended them.