If your cookies in same format as BAS, you just read it from file to variable and go Network-load cookies-set cookies for browser. If format of your cookies not compatible with BAS, compare and convert all your cookies in right format
Make sure that you are using same profile through which you
made a login previously. That works for sure.
The only thing that comes to my mind is that you accidentally
are creating new profile every time. So once you log in to
account, just edit or create new script so already created
profile is loaded again.