I use unitelvoice.com. It works fine has an app and can forward to my cell number. Used to use ringcentral.com it was fine when it worked but support was crap.
In some cases it blocks legitimate items due to naming conventions that are commonly used by advertisers/marketers.
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Examples:
LogMeIn.com - Will not display computers in your account with ublock enabled.
RingCentral.com - Logging into any web page triggers two factor but doesn't accept the response to the challenge. Turning off ubo for the page doesn't help. The extension actually needs to be disabled temporarily.