need urgent help accelerating this transaction

[joniboini]

Whenever I try this service always got "busy" notification.

Maybe because it got filled by bots since it has a 100 tx limit per hour (afaik). The best choice is always using RBF or CPFP if it's possible, other than that you'll 'fight' with others or spend a lot more to pay miners (which is still not going to guarantee your tx will be confirmed in the next block).

[tabas]

I have not tried to avail paid service.  Submission here is always beyond the limit.

Try using https://www.viabtc.com/tools/txaccelerator

I'm just using the free service.
Just as I've said, you need to check the time correctly and accelerate at exact xx:00.

Whenever I try this service always got "busy" notification.

I haven't encountered this busy notif but only the submission beyond the limit. I think that joniboini is right. With too many stuck transactions that we have in the network.
There will be a lot of people that are staying on it just to get acceleration and might even be created bots for it to auto-fill.