Mastercard complaint: My MasterCard rejected

Beginning last week my card transaction to pay for my renewal into the Canadian Firearm Registry with the RCMP has been blocked apparently because Mastercard has deemed the RCMP Firearm Registry a suspicious transaction. This morning I appealed to Mastercard Member Service helpline to have my card unblocked and was told that my card should work but today I’ve contacted the Firearm Registry 3 times to complete this transaction but have been rejected 3 times. This is a National Registry and handles hundreds of credit card transactions from across Canada daily without any problems except for my MasterCard which I was told is triggering an algorithm that is deeming this transaction‘suspicious’. I have consulted with the MasterCard Member Service Helpline 4 times today and each time was told that the transaction should go through but when it doesn’t Member Services seem unwilling or unable to troubleshoot the blocking of this transaction. The case of this issue is 1181482.