Send a web form, and then wait a few days then you might call them to check that if they have received your web form.
So deadline is Sept 29th as of now, if they give you extension of another 30 days, deadline will be Oct. 29th.
As you mentioned she is going back on Oct. 1st, she will have enough time to complete it.
Send a webform with file number and all the other details.
Also, upload the bio letter and her return ticket (if you already have one) so they can see that she is going back on Oct. 1st.
I hope they get back to you soon with an extension

Good luck !!