Les.net DOES support forwarding of their DID number to
xxxxxx@voxalot.com.
They can also be used for outgoing PSTN calls without registration.
I have never tested les.net with registration. I no longer have a DID with them, so I cannot test that feature at this time.
I suppose you would still be able to receive calls if you register that VoIP account in Voxalot, but every time the registration times out or does not re-register for any reason, you lose incoming calls.