Welcome to the board, wilson_1234! welcome
Here's an example of what is being explained to you: One of our LD PRIs is "leased" from our Long Distance Provider to our Local Service Provider (LEC), whom passes this LD circuit on to us. Although the LD provider assigns their own circuit ID to this PRI, our LEC also assigns their own circuit ID to this same LD PRI. Thus, between us and our LEC, the circuit ID for this LD PRI is 50HCGSXXXXXX. However, this same circuit is also assigned a separate and distinctly different circuit ID by the LD provider: NPXXXXXXX.XXX.

To save yourself alot of headaches, you just need to explain your dilemma to your local service provider, so that they can come out to their demarc to confirm, correctly label, and provide you with their circuit IDs, as well as the circuit IDs that are also assigned to these circuits by the LD provider. They should have no problem doing this for you.