No, honey, it's not your own debt. Can be ignored. Beware of liars
Secondly, why did I receive someone else's bill in my QQ mailbox (China Everbright Bank), and I also received this person's bill more than once?
Generally speaking, people who exclude subjective factors steal your QQ mailbox and then set it to receive bank account numbers and credit cards, and the email address is incorrectly written into your mailbox.
Third, why did my QQ mailbox receive multiple bills from others (China Everbright Bank)? ...
No, honey, it's not your own debt. Can be ignored. Beware of liars
4. Why did my QQ mailbox receive the bill owed by others (China Everbright Bank) and received the bill owed by this person more than once?
Under normal circumstances, if such a thing happens, excluding subjective factors, there should be only one possibility. Someone stole your QQ mailbox and set it to receive bank bills, or filled in the wrong email address when handling credit cards, and wrote it as your email address.