Hello and welcome to JustAnswers.
Your question about not having a combination to your safe is quite common. I must tell you right away that no expert on our site nor any other will have your unique combination to your safe. This is for safety concerns as if anybody did have your unique combination, then they could enter your safe and take what is not theirs.
Most safes asked about on our site are made by "Sentry" and they offer a simple method to retrieve your combination. Follow the instructions listed here in this link and they can then send you your combination:
If your safe is made by another manufacturer, then please let me know and I can retrieve the information to contact them as well.
Thank you for the follow-up info. As for First Alert, checking with them would be the way to go as they should have your combination on-file:
With the information provided, I feel your safe should be up and running soon. If you could take a moment to rate my assistance so that I know my help was useful and allow me to assist other customers on our site.