You may need to remove the seats out one of the other doors, then you can access what’s broken inside that door panel. It may not be the latch, it may be the lock mechanism is sticking or a part is broken. Consulting a lock-smith might work, but may not. Search this forum too, as there’s been other posts on that problem. You might get some ideas from those posts. If you decide to go it alone, suggest the removing the seats idea rather than destroying the door panel, b/c you’re likely to discover you can’t fix it anyway using that method, and then you’ll have to replace the panel in add’n to whatever else the problem is.
hmm … what else? If you think it is just stuck you could bang on it from the inside with a length of 4x4, it might pop free that way. Or it might further damage the door and maybe break the window. Another idea, suction cup devices might be able to hold onto the outside of the door strongly enough you could wiggle fore and aft and maybe eventually pull the door open, again, if you think it is just stuck, but not stuck and locked fast.
If your in a cold below freezing climate , like you live in southern New Zealand, of course the first thing to do is put the car inside so it can thaw out, it might just be frozen shut.