can a commercial debt also be held to the same fdcpa laws as a personal debt for collection purposes

I had a walk away lease on a big rig. after 18 month the radiator went out after I had just spent all my extra money on other repairs. the lease company had $18,000 of my money in a reserve account, but it did not cover the radiator. they refused to help. also, the company I had the truck leased back to refused to help. I did all I could to comply with the required termination practices with the company I leased back to. they never made any contact with me about failing to perform any of the issues, but instead sent the debt to a collection attorney group. the group is a contingency unit. they contacted by phone, and on request sent just the copy of the lease contract to me and noted the discrepancies. I disputed over half the items. some were lies. I returned items they said they never got or claimed were damaged, etc. a spare tire was a worthless casing. the decals were returned. the communication unit was not damaged. the collectors never sent me a total owed but offered by phone.