No manufacturer is going to warranty something that has been tampered with. But its also easy to ascertain that such a thing happened. If it were me, since the unit is worthless as it now sits, I would send it to them with a note explaining that perhaps they could examine it and make a determination (with documentation) as to why they think its been tampered with. At that point you would be rid of it unless they saw clear to sort it out; if not in warranty a repair estimate should precede that.
At least in the case of my car, dealer/manufacturer repairs to it are not more expensive than an independent shop. If that amp was doing the job for you the cheapest way though this might simply be to get it fixed correctly.
At least in the case of my car, dealer/manufacturer repairs to it are not more expensive than an independent shop. If that amp was doing the job for you the cheapest way though this might simply be to get it fixed correctly.