How do yall do it?

I manage a large restaurant in a historic (think hollow walls!) complex (aka we're not stand alone, share walls with other restaurants, etc.) with a mice problem. I've tried everything and we have a weekly pest service that lay traps, etc. and they point out points of entry, etc. which I stuff with steel mesh and then foam over. But they keep chewing new entrances!

So basically my question... how do yall keep out mice!?

Additionally - from my expeirence it's pretty standard that pest companies will point out points of entry, etc. but don't actually offer the service of filling them, etc. Is there another kind of company that offers that service? Like someone who will do a full review and patch / professional fill all holes, etc.?