Cant see company file

Hi There,

I have been away for 3 months and have just started back at work. I can no longer see one of the company files. I have access to one of them no dramas. Apparently my user was set to inactive for this file and has been reactivated but I still cant access the file. It doesnt appear at all in the list. 

They tried to delete my user but can't, they have also tried to add me but says I am already an active user. I had to install MYOB account right from scratch and then update the file. Not sure if this would have anything to do with it.

Any help would be appreciated!