How on earth did I get sold PPI?

Hi
I've found 3 sets of documents so far telling me/we that we took out PPI. At the time we both in employment with 6 months full pay if we were off sick and my husband had a policy which paid out as well when he was off sick. I am quite staggered that we were still sold PPI. I've downloaded the templates to start to apply for refunds. How much evidence will I need to provide that these measures were in place. I have payslips from the period my husband's refers to the policy he had for this. I did find some paperwork showing a payout from that as well.
Also, has anybody claimed anything back from what was Frizzells? Now part of L&V?

Thanks . Not expecting a fortune back but it will be useful.