I have tried  https://www.viabtc.com/tools/txaccelerator/  numerous times but I keep getting this error "elerator Submissions are beyond limit. Please try later."

It's because there's a limit in number of transactions that they accept (try it in an hour and hope for the best). Also due to the huge backlog (at the moment) majority try to use ViaBTC as well (so getting it to successfully submit is a bit hard)