Sending an external reminder and reopen expired processes

Summary

Sending an external reminder and reopen expired processes

Content

My business process has a sub process called "external details" which basically is a "on hold" state that for requests that have missing information. When it goes into this state an email is sent to the customer explaining what is needed from them.  Then every 10 days a reminder is sent to the customer. The first two emails are the same, then the last email tells them we have closed their request.

The complicate things a bit we have the following requirements:

1) if the customer contacts us in 5 days the process continues (returns to the main process) and doesn't send any of those reminders.