Hmm, you could probably do this by having a formula field that checks whether it’s been 4 months since they joined (maybe via the created time of the record?), and having an automation that will trigger off of that field to send the company an email
I’d send them an email with all of their record’s data, as well as a prefilled form URL so that they could make changes easily and submit it
Unfortunately, the only way you can delete records via an automation is with a script, so you’d need a Pro plan. I usually just end up giving records like these a status like “Delete” and then filtering them out or something
Happy to brainstorm / prototype this further