Jim is right, that is not enough to tell us what is going on with the car. If it's the Roadster electric lock, you can follow the procedure to force it to unlock, which often works, but then you MUST determine why it did this or it will just do it again.

If the latch button MOVES but the trunk won't open, it's the pneumatic lock.
If the latch button is "stiff" and won't move, then it's the electric lock.

To force the electric lock to unlock, DO EXACTLY THIS:
With the ignition “On” press the “Top Down “ button.
While holding the button turn off ignition and hold button 10 seconds.
Trunk should unlock.