[nelgaard]

That is the problem with this kind of stuff. If it was only used by aging parents it might be OK. But it will be used by everyone. Even if OP manage to somehow prevent abuse, others will just build it themselves.

Because why would you want to make phone calls in the first place and not just send an email, or an SMS?

Because of spam filters and because people do not read their emails immediately because we get so many. But now we just get the same with phone calls.

It was already bad enough with fake Microsoft support.

[ranabasheer]

True, that is the biggest problem we have with any service. There are lot of bad players that ruin it for everyone else.