FOI has nothing to do with personal data that’s about obtaining information about stuff that’s nothing to do with you say about communication between company a and b about product x.
What you’re thinking of what was referred to as a DPA SAR data protection act subject access request. The DPA has now been superseded by GDPR general data protection regulation.
Essentially it’s the same it’s just where companies were previously allowed to charge £10 to produce the info now they have to do so for free generally.
So you write to the company there are library letters online you title it GDPR subject access request. Say I want everything you have on me no exceptions blah blah blah.
They then have 1 month to get it to you