PPI Scam?

I went through and used the website through MSE to help my dad claim back his PPI. He hasn't heard from Halifax in a while. First text he got was saying they're looking into it. He told me just got a text saying this:
We have been trying to contact you re your PPI claim. We now have details of how much you are due. Reply POST for your pack or END to Opt Out.

It sounded dodgy so I googled it, the wording shares a lot with Indian scam companies. Just wondering if anyone else got this and if it's normal?