Borderlands level up problem

Hi, I am trying to level up from 58 to 59 level. I have first three DLC's but I am not getting any XP from the kills in second DLC. I can see that there is an empty gap between my current experience and the maximum one but as I said before I am not getting any XP.

Maybe someone knows the answer to this question?

Thanks.

If you're talking about Moxie's Underdome, I don't believe you get experience in that one. At all.

In mad moxxis underdome riot, you get a small amount of XP when completing the challenge, whether it be 5 rounds or 20 rounds. that is all. no XP for each kill.