It's not the junglers job to get you ahead though, if your teammate is playing someone who can snowball harder, the jungler probably wants to snowball them as quick as they can. Now, if that jungler is trying to gank an enemy under their own tower, either he's a pro who knows what he can get away with (doubt it) or more likely, is not the greatest jungler.
But if the enemy jungle is camping you top, farm under tower as safe as you can, and then remind your team to use the advantage. That's the important part right there. If you're getting camped, that's less pressure their jungle is putting on your other lanes. Safely bully him as much as you can, and then tell mid to roam bot, tell jungle to shove mid, tell bot to secure every last dragon.
Again, part of this is teamwork, which... isn't always easy. But if you're getting caught in the first couple ganks, you need to be more careful. Regardless of who you're playing, getting caught is your fault - I know you probably know this, and I know it's shitty to hear, but I'm not trying to put you down - I'm a jungle main, and when I'm forced to go top, I get wrecked by the laner because I can't pressure or CS for shit. But I can see ganks coming a mile away, and they rarely catch me. If you're having trouble against a jungler, play that jungler for a bit. Try jungling. It gives you so much more knowledge about lane pressure and map awareness that I highly recommend it. Since you're a 20, it's going to be hard. Start in bot games. Play WW. Just get a feel for how jungling works, and I promise, ganks will start to hurt less.