My stepmom and dad are pissed at my mom cause she is a little behind on child support and im tired of it.?

i know its none of my business but i think im old enough to know about it (im 15). i just moved to live with my dad and stepmom. my dad makes over 50k and my stepmom makes over 130k. my mom on the other hand is single, handicapped (not extremely), and only makes 35k a year. my mom has been having to pay $400 a month (child support) and is $200 behind in payments. my stepmom and dad are mad that she cant keep up with the payments! im extremely aggrivated that they make all this money and they expect my mom to be rolling in dough! my stepmom even stated at one point that she needed that money to have enough to keep me! wtf! i believe that a family making over 180k a year can support a teen! i mean come on! im thinking of moving back to my mothers after this year but after i heard that, i want to move back even more! i just dont understand why they act like they need the money. my dad used to be behind on payments all the time so why cant they cut my mom some slack? geez im so frusrated!