Why doesn't my headphone jack work?

I don't know exactly what is wrong with my phone (moto g3) , but whenever I plug my headphones in properly, they don't work. The only way I can get them to work is if I only plug them in 3/4 of the way and wiggle them about a bit, but as you can imagine this leads to them coming loose quite frequently. When I plug them in all the way, the sound just comes out of the built-in speakers, as though the headphones aren't even plugged in. I'm certain that it's not an issue with my earbuds, as they work perfectly fine on any other device I own. I've already looked at several repair guides, and none of them have worked for me so far.