>is there a way of me extracting the necessary files and changing them to disable debuggable apk and re uploading the application to the play store.
Unfortunately no, not without the original signing certificate.
>I understand that mobi one in it’s previous design software before updating, used default certificates for upload on the play store which were debuggable,
Let me correct this statement because it was never our expectation that some users would upload an app signed with a dev certificate to the Play Store. As a convenience MobiOne has always supported building an android app that is signed with a temporary developer certificate. In earlier version of MobiOne we provided documentation that warned users MobiOne to provide their own certificate for signing of finished apps that they plan to distribute or uploaded to Play Store. And we provided a super simple cloud utility to create these certs. But MobiOne did not force users to explicitly provide a signing cert for finished apps. This resulted in some users uploading apps built with a dev certificate to the Play Store. Once we realized this was happening we immediately revised App Center to no longer allow it.
Apps such as your’s can not be updated because there is no explicit certificate available. App Center projects have always been treated as temporary and disposable. Our policy has always been to maintain your project on app center for 50 days from the most recent update. Thereafter it is garbage collected to return the storage for the use of other developers. Thus there is no way to access the dev certificate used to sign your app originally.