My friend is just working on that problem right now. CBSA hardly collects the I-94 at land crossings because they anticipate people to go back to the US again. In the past he will just send the I-94 back to the US Consulate here in Canada. But now its all changed - he got a letter with the following:

Dear Sir/Madam

Re: I94 Arrival / Departure Record

8. Other: Please refere to the information or instrucutions at the back regarding returning your I-94 (white or green) Arrival/Departure record.

The US DHS announces that, if you left the US with your Arrival/Departure Record (I94 white or green) still in your passport, your departure was not recorded. It is your responsibility to provide the DHS sufficient information to properly record your timely departure from the US.

If you do not show a timely departure from the US, or if you cannot reasonably do so when you next seek entry into the US, DHS may conclude you remained in the US beyond your authorized stay. If so, our visa may be cancelled, your entry into the US may be barred and you may be returned to your foreign point of origin.

To show your departure, DHS will consider a variety of information, including, but not limited to:

- Original I-94 (white or green)
- Original boarding passes that you used to depart the US
- Photocopies of your entry or departure stamps in your passport indicating entry to another country after you departed the US (copy all passport pages that are not completely blank and include the biographical page containing your photograph)
- Photocopies of other supporting evidence that shows your name / departure date, to indicate you were in another country after leaving the US, such as:
> Dated pay slips or vouchers from your employers outside the US
> Dated finanical records showing transactions outside the US
> School records showing attendance outside the US
> Dated credit card receipts, with the credit card number deleted, for purchases made outside the US

Your statement alone, without supporting evidence, is insufficient. If you send original materials, please retain a copy since DHS cannot return original materials after processing. To help correct your records quickly, please include a signed, dated explaination in English.

Please mail your explanation and supporting documents to the following address:

ACS-INU SBU
PO Box 7125
London, KY 40742-7125
USA

Do not mail your I94 or supporting documents to any US Consulate or Embassy, any other DHS office or to any addres other than the one stated above. Only at this location can DHS make te necessary corrections to your records to prevent serious disruption to your US travel in the future.