Yes, it makes sense, having been a Tier-3 Tech support my self.
It's not easy when they give you NON-SEQUENTIAL D-I-D numbers.
The problem is, you can only massage 2 sets of DIGITS with D-I-D.
Is PRI an option from this vendor? (That would take a T1 card, rather than D-I-D)
With PRI, you can have 16 TABLES to switch routes around.
These things take planning and coordination between the folks who program the switch and the people who sell the service.
It looks like that didn't happen here.
If you can get the vendor to give you something SEQUENTIAL, you will be a lot better off.
What they are providing you now, may not be able to be used.