I had a dog that I'd rehomed, he had been treated poorly by his original owner. I gave him a new home and took on all his medical conditions.
When his eye took bad for the third time I approached the RSPCA to see if they would help. I was informed that I was "outside" of the catchment area so wouldn't receive any help at all.
Following his operation (the third) he was deemed so poorly and I had no choice but to have him put to sleep, for his benefit not mine.
I would never leave anything nor would I support anything that they do!!