Call the Veterans Administration (VA) contact number (1-888-GIBill-1) between 7:00am and 5:00pm Central time. There is also a form to submit questions via the VA website, but it generally takes three to five days to get a response. You will likely be instructed to call in to verify personal information before you are given any details on your account.
Follow the automated prompts to speak with a VA representative. The prompts change frequently and the VA automated system is extensive, so be patient and keep telling it you want to speak to a representative. You will soon have one on the line.
Give the representative the details of your service dates and Social Security information so they can verify your GI Bill account. They will then be able to tell you the number of months you have remaining at full benefit amounts.