Need to update to stronger password

Someone is trying to share a file with me and it requires me to change to a stronger password.  It take me to a page where it asks me to enter my old password.  It already has a password inputted there, but when I try to create a stronger password it tells me the old password is wrong.  If have tried deleting what's already inputted and enter in my current password.  Doesn't work.  Have tried every other possibility that I can think of for the old password and it tells me it's wrong.  I called support and they said they created a ticket and I would receive email confirmation in 5 minutes.  It's been over 30 minutes, I have not received confirmation that there is an open ticket.