Collaborators unable to edit after upgrade to pro

PG Yachts
PG Yachts
edited 10/21/21 in Smartsheet Basics

We have recently changed our subscription to pro due to the growing number of sheets required. However since then my collaborators both free and paid users can no longer edit sheets owned by us. Permissions have been set to edit and even change their permission to admin but no change. I have informed Smartsheet and tried to call but no reply. I need this sorted urgently as greatly effects the daily running of our company. Any help greatly appreciated.