I have four heros at lvl 130 and a few at lvl 70 and it's telling me it's maxed out. Is there something..

The max level will depend on the Star rating of the hero, however these will not be completely maxed. At levels 10, 30, 70, 130, 210, 310 you will need to Evolve the hero to continue upgrading the level. To Evolve you need Combat manuals which you gain from completing the Campaign missions. It is likely you are missing some.

Go to the hero screen for any hero you want to level up and tap on the Evolve option. It will let you know what is needed.