I'm guessing they can't open the car via the fob due to the 12v battery being dead, or very low.
I experienced this scenario a few years ago when the dashcam had drained my battery low enough for the fob to be ineffective.
You can open the car with the physical key if you pop off the door handle cover to reveal the keyhole.
Be aware though that an intruder alarm siren will probably sound once you open the door...and it will not stop!
So, be ready to pop the bonnet quickly and have a 10mm spanner or socket ready to hand so you can disconnect the battery terminal.
As Len says, more info required. But yes, a jump start from another source will be needed.