Amazon sent me an email this morning (Jan 3, 2018) to say I have a bill but I had already cancelled my free account. I can't see what I owe (hopefully zero doll

Amazon sent me an email this morning (Jan 3, 2018) to say I have a bill but I had already cancelled my free account. I can't see what I owe (hopefully zero dollars) because my account is now non-existent. One tiny Ubuntu instance I barely used and then put on standby. Then terminated. Ugh :(