Missing IHS payment needed email for 1 child

[Nalakath]

Hi
I have applied for a spouse visa along with my 3 children.Total 4 applications. The details are below
Online application made :04/04/2019
Biometrics :30/04/2019(cochin, India)
Non priority
ECO mail received : 11/06/2019(only for 3 applications. One child email was missing )
Case not straight forward email: 11/07/2019(came only for the same 3 applications)
After a long wait send an email to ukvi 12/09/2019
Case escalated on :22/09/2019
Sponsor interview :24/09/2019
IHS payment needed email for kids: 01/10/2019. (came only for the 2 kids who received eco and case not straight forward email)
I am really worried and upset with this situation. I don't why my one son's email has not come till. On his application we haven't received eco, case not straight forward, ihs payment needed emails. What should I do now?

My husband already mailed them regarding this. But they replied they can't disclose information to any other person other than the main applicant, even the sponsor. I also mailed in the ihs.sheffield@fco.gov.uk. We didn't get any response.
My (main applicant) IHS was taken double the original amount. So thought whether it may be linked and not asking the 3rd child's IHS . And we enquired about it. But yesterday they refunded the extra amount taken from me.

I don't know what to do. Anyone who have gone through this situation, please advise me. Am really worried. How could they miss one dependant application? Please please anyone advise.

It has been nearly 6 months..... Completing 120 days...... Really stressed with this situation... Please give me a fast reply

Thanks

[Nalakath]

Please anyone give me a reply