neighbor complaining / tenant LIED about dogs

[Deborah R.]

What should I do?  

Tenants said they had one 20lb dog which did meet our explicit breed restrictions.  Just received a letter from neighbor complaining about their dogs - one of which is a doberman pincher which is not allowed due to our insurance.  Neighbor says fence is falling down and doberman tries to go through fence to get their cat.  We had it nailed back up when a hurricane came through 2 months ago.  It IS an old fence, but I thought it was ok still.  

I'm thinking of asking neighbor to split cost of fence since they want it replaced.  

But how should I handle the tenant who may have 2 more dogs there than they admitted to?  They have 17 months left on their lease, and I'd really rather not ask them to leave.  The pet addendum they signed wold give me grounds to ask them to remove the pet or to terminate their lease/evict.  

Thanks for your wisdom! 

Debby