AFAIR, permanent number withheld was not a customer selected option in that you could not add and remove it yourself, it was an administrator function, you called ‘BT’ and they set it at an exchange level , you the user could then override it on a per call basis if you wanted the Calling Line identity to be forwarded…..has this administration function been included with DV ? , it may not be ,not every function that was on PSTN is on DV , but DV has some functions not available on PSTN , it’s possible that the administration option to set it automatically for every call was not carried over to DV , in which case , you would need to inhibit CLI on a per call basis , or store contacts with ‘ 141’ as a prefix .
It possible that the customer service reps , may never have had to set up permanent number withheld on PSTN lines , let alone DV , so relatively new customer service reps may have no experience or understanding what this facility is .
