This is serious, plz help?

ok there was these teenagers livin on my estate and they didnt get on well wiv my bro, they through rocks at him, i always tried to stand up for him, but i am younger than him and the older biys just pushed me out da way, since then my bro has never stepped outside on the estate cus hes so scared. also. a few nights ago i saw these group of the same teenagers around our car, i was scared they were going to wreck it, the next morning the front lights had fallen out. we had to have them repared, then on eof the boys from the gang move house and this morning my mum found a mive scratch along the cars penger door! do you think we should move house to? or should we complain? or should we just ignore it?