Any shared hosting provider is extremely susceptible to this type of issue and this type of list just doesn't work. It's a scam. There are lots of good blocklis

Any shared hosting provider is extremely susceptible to this type of issue and this type of list just doesn't work. It's a scam. There are lots of good blocklists, but there are also lots of bad ones like this. When I worked with a company who ran email systems like this we'd always steer customers away from lists like this, in cases where we couldn't deliver mail because of it we blamed the other provider. This actually worked a lot of the time and the customer would wind up contacting the sender another way to let them know they had a problem, and fairly often they'd change lists. Our standard messaging was something like, "Google and Microsoft are receiving our emails just fine, something is wrong with the receiving service"