Can you try some test numbers :
Echo test at *600 or 600 ?
*266300
Can you reach your account from a SipBroker access number?
After reaching the Sipbroker message, enter *010xxxxxx (where xxxxxx is your Voxalot account number).
Sipbroker access numbers are at :
SIPBroker - PSTN Numbers
Can you reach another Voxalot account number by dialing xxxxxx or *010xxxxxx
Try reversing the set-up and removing TPad from your account.
Usually the outgoing provider does not affect the incoming call from another Voxalot account.