I have been a customer of American Express since 2006. They recently sent me a mail offer to open a small business charge card account with them and I applied. They approved the small business card but then once the personal card credit department discovered I am now working for myself, they decided to cancel my personal card with little notice.I accepted this without any complaint and proceeded to call the business card team to cancel the newly approved card as I'd paid it off in full / showing zero balance. The business card team declined to close my business card account, stating I needed to pay off my personal card in full first.I find this unacceptably poor business practice: Be a customer for 17 years, receive an Amex "backs small businesses" offer, accept the offer, have a long-standing relationship cancelled and then have to deal with them refusing to close the newly opened business account.