Ecomed - ********* and unreasonable

Terrible ethics displayed by leading medical equipment supplier in South Africa, i handed an oxygen concentrator in for service. they reported in writing that performance was at 75% but can be restored to 95% with service and replacement of cup seal etc. i declined the quote (opted to purchase new machine instead) and collected the old machine which i later sold the machine at very low price with full disclosure of condition to someone in need thinking that 75% is better than nothing however when the person wanted to use the machine it was not functioning at all, when i inquired with Ecomed they stated compressor packed up and machine was beyond repair, when confronted with their written report they admitted that they did not reassemble machine to its previous state after the assessment. still insisted only option going forward is to conduct expensive repairs/service - my opinion is that i am entitled to expect machine to be returned in same condition i handed it in but Ecomed does no agree ? i did the correct thing and refunded the buyer in full but am at total loss myself