The paymnet has the status Hold, and the processing status Declined by Gate, but the correspondent order was completed, and the subscription was provisioned. Why could it happen?
Amount of the order is zero.
Open the correspondent order in PBA Provider's Panel and check its amount. If it is zero, then such behavior is expected: order will be completed, and service will be provisioned in spite of the fact that credit card was declined. There is no way to change such behavior in current implementation of PBA-E. It will be implemented in future versions in scope of the feature request #PBA-52788.