It works fine, you don't need to have a mining contract or be part of the viabtc mining pool... the only issue is that they only allow 100 txes per hour to be submitted. Given that there are well over 150,000 unconfirmed transactions, every man and his brother is trying to use the tool, so it gets overloaded very quickly
The best time to submit is when they reset the tx count right at the start of the hour (ie. in the first 10 seconds!
)
Thank you so much for your info. I didn't know this before. just tried and
Acceleration succeeded . Actually, I had 2 unconfirmed transactions since 2 days ago.