i feel for you, my DAD did exactly the same thing as your mom...kinda FORCED to sign the agreement without knowing what the policy actually cover..i argue with my dad for 2 days before finally sign the damned paper just to please him. it cost me 200/month, which kinda costly when i was just a fresh grads that time.

1) if you didnt care what your mom think anymore, straight change to another agent. beware though, your mom agent will complain and things might get ugly

2) you and your bros find opportunity to gang your mom continuously, but DO NOT let the agent know. if still fail, consider use method 1

good luck