I have a game on the Play Store, recently i wanted to make an update to it. So i built my Game and uploaded it but Google Play gave me an error that says that i can't upload with a debug key. I made a new key to fix this but because i originally uploaded it with the debug key the keys didn't match. Is there a way around this?
This is currently a bug in the Play store. The upload validation process got stricter recently, and is checking for debug keys more thoroughly. But it doesn't exclude apps which already have debug keys as their upload key.
The bug will be fixed soon. However, it sounds like you use Google Play Signing, which is great, it gives you a solution. Follow the instructions on this page for contacting Google Play support for changing your upload key.