During my recent trip back to my hometown, I needed to set up a new internet broadband connection. Following the operator's instructions, I registered a local mobile number as my main number and subsequently switched it to various apps. When I tried to bind my number to Didi, the app detected that I had previously registered and prompted me to log in and cancel the account. Upon logging in, I discovered an unpaid order from around four years ago that I was unable to cancel. I had already contacted customer service, which assigned a dedicated representative to handle the issue.