The trunk will not open?

Yep, so what happens is the battery needs to be replaced, once they go dead it takes them out, they don't like to go dead FYI. This car has a specific point designated for jump-starting the vehicle under the hood, looks for the small red cover to connect the jumper too. Also, choose a good ground as well. Here are the instructions on how to jump the car:

Notes/information on start assistance (jump starting)
REP-ALG-RAE3812-120FRE

Do not start the engine with the help of starting sprays.

Preparation:

Conform with the following when starting the engine with a jump-starting cable.

Ensure that the jump-starting cable wires are of appropriate cross-section size.

Only use fuse-protected jump-starting cables.

Check whether the current-supplying battery has 12 V voltage.

If the engine is started from the battery of another vehicle, ensure that there is no contact between the bodies of both vehicles.

Important!
Never touch electrically live ignition system components: high voltage - danger of injury!

If the battery in the vehicle supplying power is weak, start the engine of this vehicle and let it run at idling speed.

Operation:

It is essential to conform to the procedures so as to avoid injury to persons or damage to parts.

Automatic transmission: select drive position ”P”, apply parking brake.

Manual transmission: move gear lever to neutral position, apply parking brake.

Ensure that the jump leads cannot get caught in rotating parts, e.G. Fan.

First connect both positive poles of the batteries with one jump starting cable (red).

Use the battery positive terminal in the engine compartment for vehicles with the battery in the luggage compartment.

Then use the second jump starting cable (black) to connect the negative post of the current-supplying battery with the earth/ground point (not the negative pole or the body) of the vehicle to be started.

Important!
Do not connect the second jump starting cable (black) with the negative pole of the battery in the vehicle to be started. Produced gas could be ignited by sparks.

Risk of explosion!

After the engine of the vehicle to be started has fired, first disconnect the jump starting cable between the negative pole and the earth/ground point. Then remove the starting cable from the positive poles. Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.

Yes, the cable is broken, that is why I would try to use the electrical portion of the latch by attaching the jumper cables to the power lug under the hood, it should have a red cover of it on either the right or left fender well. Push down on the trunk lid while you are opening it to help the latch open, then you can repair the cable release or replace the latch. Check out the images (below). Let us know how it goes.

Sounds good :)

Push down and lift up while working the latch is all you can do. There is only one latch. Can you please shoot a quick video with your phone so I can hear the noise? That way I can tell for sure what's going on.