So far I would suggest using a pwnbox as long you can access the website this should work and you got VIP+ so you can use them unlimited.
Other solution to use htbvpn might using a chain of vpns so firsty a vpn connection which is not blocked and also doesn’t block htbvpn and then use htbvpn. BUT this could be a pain in the *** to setup and also raises more possible problems.
//Edit: As a third option you can use cloud computing, aws/azure/ocean blue got some free tiers moreover I recommend using a zero budget alerts because there might be some additional cost. Nevertheless the pawnbox is so far the best solution.