Unable to RECEIVE calls on Direct Routing after portorder preloaded numbers for Calling Plans

Customer Scenario:

Running Direct Routing for 6 months, all good. Now decided to port numbers to MS to use Calling Planns instead of DR. The same day Microsoft replyed that port order was accepted and the numbers would be preloaded on the tenant, inbound telefony for endusers stopped working, we can still dial Call Queues, and also outbound dialing thorugh SBC works fine. Output from get-csonlineuser looks normal - policy is HybridVoice, phone number is set in both OnpremLineUri and LineUri, looks correct. SBC vender reports that call fails with "Number unassigned"... Any feedback greatly appreciated.