Overran with spam calls. Need help answering the phone.

[Joe S.]

So my wife and I have a real estate company.  We have people help us from time to time, but on a per job basis. 
We probably get 30 to 40 calls a day and sometimes more from, robo calls, telemarketers, and wholesalers trying to sell us a property where the numbers do not make any sense whatsoever. In the mist of so many spam and junk calls there could be a real live seller in the mix.

If all we did was answer the phone for telemarkers, we would not get anything else done throughout the day. At least that’s the way it feels after taking so many calls. We have started allowing some of the calls to go to voicemail.  I know this is not advisable, but it is what it is.

What service or method have others used that is cost-effective to answer phone calls? 

[Joe S.]

Quote from @Jonah Hartsburg:

@Joe S. There are a handful of tools to help whether this is on your personal phones or your business line. For personal, most phones have a setting where you can block unknown callers, and there are apps you can download to help filter out spam calls. If it's your business system, some of the more popular providers (Dialpad, RingCentral, etc.) come with a built-in spam filter for high-risk numbers and robocalls. You could also hire a virtual assistant as an administrator to answer your business calls while also providing general administrative support, similar to an executive assistant who helps narrow down your email inbox to the content that matters most (and is income-producing). 

Thanks for the reply.
IF filtered out all unknown calls, that would pretty much cover all the potential sellers as well. Lol.