Have a DSX 80 with 5 analog trunk lines and 2 port VM. Customer says the phone bill has random toll charges that were made while office is closed.

I could understand if this were an IP system and settings were not correct but this is just a basic setup. Any ideas?

read this

https://www.necdsx.com/docs/sales_support_mailings/2011/s0094_best_practices_11-14-11.html

thanks