How long have you had the amp thatis most important ,if only a few weeks
than any good dealer would give you an exchange ,if not expose these guys who will not work with you. Where is the repair facility ? Thsts total BS if they make it
the repair shop can either just replaces board or trouble shoot it and fix the bad part. I owned one ,it’s not that complicated by any average audio technician
ifyou don’t have a backup system have it sent to another tech , expose this
unprofessional behavior .