No receipt notice from USCIS lockbox. Could the I-485 application be lost?

[NA Parents]

I am applying for I 485 for both my parents. I mailed their individual applications through USPS at the same time (8/15/19). The Chicago lockbox received it and sent me the Receipt number (Through text and mail) for my father's application on 8/25. So far, nothing from my mother's application.
I called USCIS and they have no record of her application and asked me to email the Lockbox support, which I did yesterday. Any suggestions on anything else I can do?
Should I re- send her application? Based on her I-94 she has to leave in a month and I am not sure what might happen if I just continue to wait and see no response.

Welcome any suggestions.

[Enub4]

Sometimes it take time for them to send the information but it is weird that you already got one confirmation but not the other.

Are both tracking numbers reporting delivery the same day? Signed by the same person? Did you send checks, money order or information for credit card payment?

I think it is a personal decision, you may want to file again just to be sure, but I don't know what will happen with the money if they process 2 applications for the same person. I hope you get good news soon.

[NA Parents]

Thank you for your message. The stupidity I did was not opt for a tracking number or anything from USPS.
Although my gut feeling is since 1 was delivered so was the other, but I have no way to prove it.
i sent form G 1450 as payment ( credit card). Money for dad has been charged but nothing for my mother.

My mother also has no last name and I am unsure if that is posing a problem, but either way they should have at a minimum notified receipt of the application and charged my credit card.

i am taking steps to make copies of all forms again and resend. I will call uscis to find out what happens in case of duplicate applications.

[Msafiri]

I think the lockbox rejected one application. Usually, if they haven't deposited the money, that's the case. They will return the entire package to you with instructions on what's missing and how to resend it. It's not a big deal. For most people, it take a 30 days to receive the package.
It also takes them along time to respond to emails but when they do I found that they were very helpful and detailed.
All the best.

[NA Parents]

Thank you so much for the response and I hope you are right. Given that 30 days is very close to her l 94 date, should I extend her visa?