Users Coinbase customer care can contact Coinbase by telephone 24/7 at the following phone number. By Email. As mentioned previously coinbase customer support number , users can also send the Coinbase customer Coinbase may update the conditions for eligibility at any time. ¹Crypto rewards is an optional Coinbase offer. ²Limited while supplies last and amounts offered for each quiz may vary. Must verify ID to be eligible and complete quiz to earn. Users may only earn once per quiz. Coinbase reserves the right to cancel the Earn offer at any time.