Can't get the web version to work for you or the FilmBus app APK doesn't support streaming via the website? One alternative is to use an Android emulator on your computer, and then access it at arm's length on your iOS device.
What’s an Emulator? It’s software that you download and install, and it emulates an Android device on your computer. For example, BlueStacks is a popular Android emulator that can play mobile apps on a computer.
You can use Android emulators to run Android apps and APKs like FilmBus on your iOS device. Of course, you can only watch on the PC (not on a phone), but at least you have a way to watch.
BlueStacks Safety Note: BlueStacks (and other emulators like Nox, LDPlayer) are very safe and used by millions of people. Just keep in mind to always download the emulator from the official website and never a hacked one. In other words, an emulator is a safe, legal, and easy way of running FilmBus APK on your computer.