If you have not the power to write to the admin then ask your boss to do that. 30 minutes waiting to post a goods receipt is minimum 29 minutes too long. This must not even be explained, just tell the material document or schedule agreement where it happened, a support guy should be able to test this case, to search for OSS notes, to contact SAP.
You should actually have a local help desk and a ticket system which is to be used in case of problems. If the system are well setup (which I already doubt) then you can just open a ticket from within MIGO by double clicking the SAP name in the lower screen section in middle. This will open a window to enter the text and is then routed to the responsible support persons.