EastLink is having problems with their systems right now, which is expected when systems and processes are completely new. It gives me a head ache everyday.
I work for CityLink (dont shoot me) and know how the system works.
My advice is to call them and find out if there is anything outstanding for your rego. If your lucky their system may have had a melt down at the time you travelled. If you are things have progressed from the EastLink Late Toll Notice your in trouble.
The next port of call is Civic Compliance Victoria (CCV) and a $113 fine, which if you want to contest you won't have a leg to stand on, not even if it went to the wrong address. Its simple, you used EastLink and failed to pay within 3 days and there response to "i never got the notice" will be the same. It is your duty to ensure they have your correct address at all times.
Also be aware you will be fined $113 for each day of travel and CCV have up to 12 months to issue a fine.