Accidentally add funds to my account

I understand how frustrating it is to misplace your money, xu wenjia.

Unfortunately, if the $50 has already been redeemed and is showing as Microsoft account balance, it cannot be converted to cash or similar payment products (except where required by law).

That said, since this was an accidental transaction, I would still recommend contacting Microsoft Store Support and asking whether they can review the transaction and make an exception:

1. Sign in with your account at Contact Us - Microsoft Support   
2. Enter / choose an issue > click Get Help to make a request     
3. Scroll down > click Ask our Support Assistant and follow guidance   
4. If the issue persists, specifically state in the chat box that you need direct help.   
5. The Contact Support button should appear > click it > select the chat in browser option.

Note: The support contact team only works at certain times, so if the last window shows that it's unavailable, try opening it again the next day. If you prefer phone support, you can leave a phone number. This way, they can call you and help you. If you don't see chat option, choose another category and ask to escalate. 

I wish I could help more directly, but payment-related issues often involve privacy information. Microsoft Q&A is just a user-to-user technical support forum, we cannot access your billing account or process the refund here.