This is a scam call, They ring you and then hang up when you answer. If you call them back on this number, Not only are you paying for the call but they know you are a mug who is ripe for their Reclaim PPI tax and other finance charges patter.
They are scum who are looking for gullible people to con and judging by their reviews if you are stupid enough to use their services, Will charge 50 per cent.
Hopefully they will all catch XXXX XXXX XXXX.