VPN blocking and limiting

In short - two windows-based PCs, connected by VPN tunnel passing through 2 MTs.
I want to block all users except 10.20.2.80 user from using VPN and at the same time to limit that user to max.30kB/s in VPN.
Is this a right configuration?
Some users from 10.20.2.0/24 network say that they are having VPN with NET-link network limited to 30kB/s.
So, what am I doing wrong, since all users can use VPN limited at 30K?


MANGLE:

19   ;;; joza vpn
     chain=prerouting src-address=10.20.2.80 protocol=gre 
     dst-address-list=NET action=mark-connection 
     new-connection-mark=joza vpn passthrough=yes 

20   chain=prerouting connection-mark=joza vpn action=mark-packet 
     new-packet-mark=joza vpn passthrough=no 

21   chain=prerouting dst-address=10.20.2.80 protocol=gre 
     src-address-list=NET action=mark-connection 
     new-connection-mark=jozavpn2 passthrough=yes 

22   chain=prerouting connection-mark=jozavpn2 action=mark-packet     new-packet-mark=jozavpn2 passthrough=no

FIREWALL FILTER:

 2   
;;; VPN  DROP
     chain=forward src-address=!10.20.2.80 protocol=gre 
     dst-address-list=NET action=drop 

 3   chain=forward dst-address=!10.20.2.80 protocol=gre src-address-list=NET 
     action=drop

QUEUE TREE:

10   name="joza vpn" parent=NET-Link packet-mark=joza vpn limit-at=0 
     queue=default priority=8 max-limit=245760 burst-limit=0 
     burst-threshold=0 burst-time=0s 

11   name="joza vpn2" parent=NET-Link packet-mark=jozavpn2 limit-at=0 
     queue=default priority=8 max-limit=245760 burst-limit=0 
     burst-threshold=0 burst-time=0s