Why do i keep getting stuck in my mailbox on

Hello,
Why do i keep getting stuck in my mailbox on the sims 3?

does anyone know the answer

this would be a great help

when i go onto my sims house, they just get telported into the middle of the mailbox?, and they cant move, they try to do things themselves but they just flicker on and off, ive seen this question before but its never been answered, please help