What is the problem? Please be detailed.
What ODK tool and version are you using? And on what device and operating system version?
What steps can we take to reproduce the problem?
What you have you tried to fix the problem?
Anything else we should know or have? If you have a test form or screenshots or logs, attach here.
There are many kinds of quotas associated with Google App Engine; you can look at this page to see all of them and find out what you have exceeded.
Once you figure out what you have exceeded, we may be able to give additional advice, but the likely answer is you'll have to set up a new account and a new server with fresh credentials and take care not to exceed the quota again, or you can pay Google to make the problem go away.
@mawulii In general, your Aggregate server should not use quota if you are not using it (e.g., if your web browser or some ODK tool is not connected to it). If you have run out of quota, you can either enable billing (as @issa suggested) OR wait 24 hours for the quotas to reset.
If you provide more information about the version of Aggregate you are using, the steps we can take to reproduce the problem, and what you've tried to fix the problem, we can likely offer more assistance.