I can only comment that there is a default tolerance of 15 days built in for OM (which probably triggered your question 20 working days later.
People normally only complain when they loose access... so it could also be a lot of things. Personnel status (select no longer performed) or personnel number changed (IT 0105 no longer matches)?
Unfortunately HR is riddled with macros in the LDBs which you cannot debug easily, but it is always worth a try to see whether your data is the problem or the program.
If you cannot debug it then I would suggest that opening a customer message with SAP is the fastest route.
Little tip: Describe the problem well and suggest the solution after debugging and use priority "low" -> a ninja will find it as a "snack" and fix it very fast or tell you what the problem is... ;-)
Cheers,
Julius