Is there any way to blacklist a contact to prevent them from connect?
Can API used for this?
Check this link:
If this helps you answering your query
Using the RingCentral Phone for Desktop, you can dial or receive test calls, send and receive test SMS or Fax messages in your sandbox environment.
Download RingCentral Phone for Desktop:
Tip: switch to the "sandbox mode" before logging in the app:
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