Annotations disappearing intermittently and saving is slow

Hi

We have Adobe Acrobat XI 11.0.16.  We paid for license.  Question - is there a phone support?  We need help soon.

We have one staff have annotations disappear intermittently.  3300 pages full of annotations and comments.

When she opens the file, there were missing annotations.  she closed it, and she reopened it and now she finds them.  Also hyperlinks missing sometimes.

Also, when she saves the file, it takes approximate 2 minutes the whole acrobat app freeze.  85 page document saves in a second!

She saves locally.

Intel Core i5 4310U CPU 2.6Ghz

8GB RAM

64 bit Windows 7 Enterprise.

She shared the same file to another staff. the other staff is using Adobe Acrobat 11.0.10 and she can't see the new annotations she placed.  There were missing.

Please help.  Documents are time sensitive and very critical  not to lose the annotations.

Thank you

Adel