When you entered the US, you had to fill out either a white form if you entered with a visa, or a green form if you did not need a visa. Upon leaving the US, you are supposed to surrender that I-94 form to the US government. But sometimes that does not happen. For whatever reason, the airlines or whoever it is forgets to take the form. So now the US thinks you are in the country illegally, past the date stamped in the I-94, and you will have problems.
If this happens, please mail the I-94 back (certified mail) other documents to prove that you are out of the country, to:
1084 South Laurel Road
London, KY, 40744
Documents to prove that you are out of the country can include, but is not limited to the following documents:
1. Original boarding passes you used to depart another country, such as Canada, if you flew home from there;
2. Photocopies of entry or departure stamps in your passport indicating entry to another country
3. after you departed the United States (you should copy all passport pages that are not completely blank, and include the biographical page containing your photograph); and
Photocopies of other supporting evidence, such as:
4. Dated pay slips or vouchers from your employer to indicate you worked in another country after you departed the United States,
5. Dated bank records showing transactions to indicate you were in another country after you left the United States,
5. School records showing attendance at a school outside the United States to indicate you were in another country after you left the United States, and
6. Dated credit card receipts, showing your name, but, the credit card number deleted, for purchases made after you left the United States to indicate you were in another country after leaving the United States.