It's just, a bad jungler, which is a common appearance in low level/bronze etc, is just 100% useless to the game, a dead weight, never where he needs to be, always where he definitely should NOT be, not building what he should, feeding or taking easy kills in an attempt to "carry", pushing your lane when you definitely do not want it pushed (for example, frozen), taking your farm in general, and so on and so on, and then they just kill the game. When people "blame" a jungler, it's rarely going to be for a single occurence or mistake, but for the general picture. I for one have long given up relying on my jungler, I play like we have none (I main toplane), because that is, sadly, usually what it comes down. I hope it gets better in higher ranks, but from gold and even plat friends I am hearing sorry tales still. It just seems getting the jungling right is rather hard.
That said, after your second buff, you generally go top. The other jungler will be there and instead of a 2v1 and a possible first blood on your team and a very likely lost toplane as a result, it will be 2v2 with a possible first blood and maybe even a double kill for your toplane. You do this even when your toplaner is pushing the lane, because, again, enemy jungler if he knows what he's doing will be there.
Good luck on your jungling adventures, hope to meet you in game.