Frustrating isn’t it.
The person you need to contact could be the MD of a large company that you can supply apprentices to. Or they could be the perfect guest speaker at an event you are running. But if you can’t email them you have a problem; especially if the gatekeeper assiduously guards them.
You could look for them on Facebook or LinkedIn but that takes time. Their website might only have an info@ type addresses.
Finding email addresses
So check out emailhunter.co .