Why Can't Some DID on DIDX be Used on Calling Cards?

So, your IP communications company, CLEC, hosted VoIP provider service, or wireless operator business has a DIDX account and is buying SIP or IAX DID in wholesale and in turn, reselling those DID phone numbers from 60+ countries to your end-users, both individuals and groups. Why is it that some DID on DIDX cannot be used on calling card platforms?

Answers directly from DIDX vendors and we will add more as receive answers:
1. The provider typically doesn’t care. The only reason it usually would say NO for using on calling card platform is because of regulatory reasons. So if the government regulatory organizations do not approach us based on a complaintm then we don’t care how the DID is used. Uf the regulatory approaches us with a problem, then we will have to cut the line. So I believe it will all depend on the regulatory regime for telecom products in the particular country of the DID phone number.

2. There may be a regulation such as from Indotel, PTA, or BTRC (the regulatory institutions in Dominican Republic, Pakistan, or Bangladesh) that prohibits the use of regular DID numbers for calling card applications. If this were true, it would be indicated to Super Technologies, Inc. regarding the DIDx service it runs with several e-mails and documents pertaining the matter.

In general, the seller of the DID numbers does not pre-emptively take measures. If another carrier/operator/whistleblower brings the matter into the DID sellers' and Indotel's attention, then the Indotel will issue a cease or desist order, and probably accompany it with a suspension order.

3. Some incidents that a DID seller or government authority would request cease and desist and possibly suspend a number with suspicion of calling card use where not allowed.
A. A whistleblower tells the authority.
B.  The number is listed on calling cards.
C. The number has calls routing through it 24/7.
... Are you an IP communications related entrepreneur, telco of any type, wired or wireless, contact center, social or business community portal provider, conference producer and such? If not, find out how to get your telephone company to offer phone numbers from around the world.