Saw a Facebook ad regarding compensation for opting out of SERPS. Should I be concerned?

I'm 38 and around 20 years ago I was given the option by my employer to opt out of serps and set up a private pension with Scottish Widows. I recently saw an ad on Facebook that claims I could be due compensation for this, which the advertiser will help with on a no win no fee basis. Is this something I should be concerned about? [Pensions]