While the situation indeed sounds unfortunate, this is something that Ethiopian stresses to you many times over during the booking process.
Indeed, when making payment on the website, you get the following warning - in block capitals and red font.
FOR PAYMENT WITH ALL TYPES OF CREDIT/DEBIT CARDS, CARDHOLDER MUST EITHER BE ONE OF THE PASSENGERS TRAVELLING, OR MUST BE AT THE CHECK-IN COUNTER WITH THE TRAVELLER/S WITH THE CARD USED FOR PAYMENT ALONG WITH GOVERNMENT ISSUED PHOTO IDENTIFICATION DOCUMENT (PASSPORT/DRIVING LICENCE ETC) PRIOR TO ISSUANCE OF BOARDING PASSES. ALTERNATIVELY THE CARDHOLDER MUST PRESENT HIM/HER SELF IN PERSON TO AN ETHIOPIAN TICKET OFFICE PRIOR TO THE DATE OF TRAVEL WITH THE CARD AND I.D. AS STATED ABOVE. FAILURE TO PRESENT THE CARD AT CHECK-IN OR AT A TICKET OFFICE, WILL RESULT IN A NEW PAYMENT FOR THE JOURNEY BEING REQUIRED OR TRAVEL WILL BE REFUSED. PASSENGERS WILL BE DENIED BOARDING IF FOUND TO BE TRAVELLING WITH A FRAUDULENT CARD.
You can avoid this issue by booking via Expedia or another OTA, rather than directly with Ethiopian in the future.