Can I stop my auto-pay plan if i don't remember my phone number?

Hi,

I'm out of the country now and didn't cancel my AT&T auto-pay plan before I left. I know it sounds ridiculous but i really don't remember my AT&T number since i bought the number just for temporary use. Now it gives me trouble that it charges me every month and I don't know how to cancel it. I couldn't make an international call for now. I really need help to cancel the plan without making a phone call if possible. 

I hope AT&T Customer Care can see this and help me out. Please let me know if you need anything from me to solve this issue. Thanks!