Crazy cell phone problem

first off, i have verizon

when somebody trys to call my phone, it will ring and stuff, but if they leave a message on it, the message thing that pics up is to another family or some shit.

for example, if my mom called my phone to leave a message, the thing that she would hear before she leavs the message says "hi, youve reached the (other family's last name). please leave a message and we'll call you back."

then when i try to pick up my messages, it doesnt ask me to put in my password, but it rings, then goes to the same answering machine thing that isnt mine. so i cant pick up my messages! what the hell happened? im calling verizon later today if nobody here knows how to fix it though.