Very important document signed, did not receive an email back

I just got an important document from HSBC to sign. I have signed it, but did not receive the email back with the signed document. Really, really important document. I have checked spam, inbox, nothing. There is a time issue as well, I have 10 days to sign the document or the application is canceled. What should I do? It can take a day or two for the email to appear?