Government blocked Internet sites

I understand to some degree in Indonesia why some internet sites are blocked especially pornographic sites, terrorist groups, etc.  I can even accept I guess blocking gambling sites, but I can no longer access my bank's site to use up my rewards for trips,  since it has now been blocked because the word “reward” in it, suggests I guess, gambling.  And I am not sure what to do?

Some are government blocked, others done by your ISP.
I use several forums, some can't be accessed on one ISP but can on others.
Start with your service provider as they might well be able to solve the problem.

I've had similar issues in the past for everyday/ ordinary websites, if your ISP can't help or won't help try a VPN but that could give you issues if your virtual location changes, especially with your bank back home and may red flag your account

I strongly recommend VPN, Find a VPN provider that gives your home/bank's country as the virtual location so you don't have virtual location issues. Run an iplocation check after connecting to ensure all traces are your desired virtual location (i.e. your home country/bank's country).
Having VPN nowadays is best practice to avoid hijacking of your personal data by cyber criminals.