The mailman claims he was bitten by my dog and now won't deliver my mail: Help!

I have a problem with the post office. They claim a mailman was biten by one of our dogs. I have three pitbulls, but there is no way they can get out as the yard is fenced in. My next door neighbor has a pitbull who gets loose all the time and is walked without a leach. Anyway, the mailman lawyer contacted my homeowner’s insurance and they are handling the case. In the meantime. Every since the mailman got bitten (going on two months$ the post office refuses to deliver our mail, so we go to pick it up twice a week. Today I was told I need to rent a PO Box because we can’t keep going to get the mail through them . The PO Box cost $99.00 every six months. I refuse to “rent” a PO box when it’s them the ones who refuse to deliver my mail. So I take the time to go pick it up twice a week. Now the post office staff do not want to serve me unless I rent the PO box. I feel my rights are being violated. And it is a federal crime to mess with anybody’s mail. Anybody knows what I should do to denounce what the post office is doing??