1) CICS does not support direct PRI.
2) After the local C.O., that call is riding DS3 or Sonet to wherever it is going to. DS3 or Sonet issues do not show up as errors on the local DS1. Until enough people complain (and have specific information for the provider), the provider will not deal with it. Make sure your DS1 is clean first (since problem sounds like LD only, it probably is, but make sure!).