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.
https://himss.zendesk.com/hc/en-us/community/posts/36864150492051--FACING-ISSUES-WITH-YOUR-Coinbase
