If I close the SMS service at ABC, do I need to pay the SMS service fee that I failed to collect in the past few months?

Yes, it needs to be paid to the Agricultural Bank of China.

If you want to close the SMS service in ABC, the SMS service fee that has not been deducted successfully in recent months must of course be paid to ABC in a certain form, otherwise it will not only cause late payment fees, but even have a certain adverse impact on your reputation.