Considering his age he probably just forgot to call you. I would try calling him again. It can’t hurt.
That was my first thought. I've met Mr. Enzo -- an elderly man -- and found him to be very charming and quite committed to providing conscientious service to his customers. He seems to be very confident that his product is topnotch and backs it wholeheartedly.
It was 3 years ago when I met Enzo in Atlanta and I guessed his age to be late-seventies. I remember that fact because I followed him from his garage in North Atlanta to a suburban area south of the city. Something that struck me about him was how fast he drove his Jaguar (speeding at over 75 mph). I thought this old man is going to kill somebody and himself if he doesn't slow down.
Enzo was quite alert and lucid when we met, however, at his age mentation can decline rapidly, or it can decline gradually. That would account for the forgetfulness.
I don't write the above to rationalize poor service, as I understand that customers who spend nearly 4k on a compressor expect first-rate performance and service.
My Nardi Atlantic 100 has served me well for ~ 5 years.

The only hiccup I've had with it was a failed on/off switch, which Enzo replaced himself, even though the warranty period had elapsed.
Give him another call and remind him of your issue. I'm betting he will provide the service you expect.