In tcpvpn, you can use your ssh ip server as your squid proxy or else, use squid proxy at ssh menu. If your ssh server is in poland, use that ssh ip as your squid for fast connect and compatibilty. If you tried everything with regards to payload at no avail, then all your free sites is already filtered. You can't do anything about it. You can avail isp promos that provides free or unlimited social network like facebook, viber, instagram so on and so forth, using that as your payload host and bypass that using http injector.