Port your phone numbers out ASAP, you can jump to Teli or BulkVS and pay quite a bit less with much broader numbering inventory available.
The FCC has defined these SLAs and if you ever have a losing provider that is close to breaking the SLA on a port request, search for the providers local number portability escalation list and call each contact until resolved.
Voxbeam and Anveo Direct are solid choices for international DIDs.
Bandwidth.com has a poor reputation FYI, they pissed off a few Public Utility Commissions and were blacklisted from getting new phone numbers in some states.