Passport may be lost in the post

We're new to the forum but were hoping someone may be able to help.

We started our permanent residency in the UK in Oct 08 but were able to get a work Visa in the meantime and are now living and working in Alberta with the permanent visa going on in the background.

We let the Canadian High Commission know that we are living in Alberta however they continued to use a UK address for contact and we then had to wait for letters from them in the UK to come to us in Alberta.

We were asked to send our passports, work visas and a confirmation form to them in London UK. This we did on August 10th via registered post through Canada Post on a seven day delivery so that we could track the package. The documents left Canada and were received into the UK 4 days after being taken to the post office (which was great) however it's now August 27th and Canada Post still can't confirm or deny whether its been delivered.

Our cut-off date is September 5th and we've been able to get Canada Post to open an investigation to see what has happened to our documents as we are now very worried that they have been lost at the UK end. We have sent the Canadian High Commission a fax to find out if the documents have arrived but not heard anything.

Can anyone advise as to what we could do next and what happens if all our documents have been lost?

Thanks in advance.
K