The temperature inside should fall in a few days.

I have two safes of that style (but the larger 5ft versions)
I got them the day we moved into this house. The guys bringing them had to wait several hours for us to get into the house. It was a hot day and they were on the back of the truck with the doors slightly open. When they were installed they were very hot inside (Id say over 89 degrees).

Now, even on the hottest day, the temperature inside rarely gets above 50 degrees.
The metal inside should work like a 'thermos'. The only thing that will stop the temperature decreasing is if you leave it open a lot.
I only open them for minutes at a time.

Here is something you can do to lower the temp quicker. Lock a bucket of ice in there overnight. Remove the shelves (if there are any) while you do it.