My experience with P2P on mobile is, that both ISP i had, didnt support port forwarding. For me in Germany it was O2 and Congster (uses the net from Telekom). My Cable ISP now is Unitymedia in Germany, they have these network, where it is impossible with port forwarding too.
I had nearly a year TorGuard for VPN, but then it doenst work anymore with high id or positive NAT Test with torrent. After i read a lot and tried some other, the only working VPN Service for me is AirVPN. Cheap, own Software, good performance and easy port forwarding. Even i could do it after some time
I doubt there is a mobile ISP that supports port forwarding in germany, dont know for other countries. Maybe out of EU?