Amex Prepaid Card Complaint

Amex Prepaid card department,

General purpose card Managing, opening, or closing account Texas

Hello - I am a American express credit card member and have a - credit card. For the last many months, Amex has been sending me emails on Serve prepaid card and has also send me a physical copy of the card. After waiting on the line for 75 minutes, when I requested them to close the card as I did not request for it, they came back saying that unless I spend a minimum of $50.00 on the card, they would not be able to take any action on this card. 1. I never requested for the card 2. I keep getting unwarranted emails from them 3. After spending more than an hour on the phone, I am told that I am not authorized to close the card that I did not ask in the first place. I am not sure I understand the logic here.