I contacted them before I bought they said since I was a self-installer they would work with me on any issues. They do require an envoy and they always have you swap the inverter to another panel to verify it is the microinverter that is bad.
What version of microinverters do you have?
There is nothing in the warranty that says it has to be a registered solar installer. I would talk to others at the company higher up. If that did not work I would contact the BBB and the attorney general office.
If you use twitter I would tweet about it they are very responsive there.
I keep a spare M215 microinverter on hand just incase one goes bad. I will swap it out and send the bad one back to them I don't want to be not making power waiting on the replacement.
https://enphase.com/sites/default/fi...A_Steps_WW.pdf
https://enphase.com/en-us/warranties
I just read the warranty it does not state “registered solar installer who contacts them” anywhere.