You're absolutely right. I sent a customer service request through the app and they responded that deactivating Alexa to Alexa calling and removing contacts must be done by phone or chat. I should have weighed the inconvenience of saying "Alexa, call Tom" vs "Alexa, call 222-222-2222" with the consequences of having lots more personal information on Amazon's servers. Using a Google voice number is a great idea and I may go back and reactivate with mine once I solve this problem.