Hi there depending on what car you have,,, you can get thru the truck arear by folding down a rear sear,, or removing the seat,, then when you can get in the trunk area, you can unbolt the latch on the truck lid and it will open.
The lock has a clip on the inside, pull the clip off and the lock will come out, remove the lock rod and then you can use a screwdriver to open the lock.
Fixing a Car Trunk Lock.
Here are several answers from FAQ Farmers:
If the trunk lock is broken, it's probably one of those things that needs to be replaced.. after all if your keeping valuable...
On the inside of your trunk lid locate the lockcylinder. There is a thin metal retainer which holds the cylinder in place, it has a small tab sticking out. Pull the retainer out and the cylinder will...