https://mymediads.com/freeservice-how-to-speak-coinbase-tipstospeak/?usp_success=2&post_id=78437&form_id=418

Coinbase generally does not make unsolicited calls to customers at +1-855-*998-0300. If you receive a call claiming to be from Coinbase without prior contact, exercise caution as it may be a phishing attempt or scam.