Comment by lgl

A perfect anti-spam solution doesn't exist.

Even if you switch e-mail provider, as long as they're also using some sort of anti-spam system, false positives will always happen occasionally.

The obvious recommendation is to always add any trusted senders to your contacts or, as you've already done, create some filters.

Alternatively, switch to a provider that doesn't use any spam filtering at all. But that will open up a whole different can of worms.