I just use the free Spamassassin. It requires some technical knowledge to install and configure, but once done you can filter all your mail through it. If you’re not technical you can no doubt contract someone to install and configure it for you.
I do get the odd spam that it misses – it’s not that good at picking out the stock alert spams which usually contain just a single big graphic – but it catches 99.99%, and you can manually train it on messages it misses so eventually it will start catching them.
It’s caught 11,000 spam messages in the past month.