Help needed - ESA form sent via recorded delivery

Hi ,
Really worried & need some help. I recently completed an ESA form for movement from Incapacity Benefit to ESA & returned it via Recorded delievry on the 09th of August 2012.
I have checked Royal Mails' track & trace service & it states upon entering the trace number --- " ... it is being progressed through our network for delivery .... ".I rang Royal Mail customer services & they have no idea if it has been delivered or not .
Im really worried as my claim has to be with Atos at Wembley by the 15th - this Wednesday or my money will be stopped .
It was sent to the po box 1044 address in Wembley .
How do i find out if it has arrived with Atos by the deadline ?
Any help woud be most appreciated ; thank you.

Hi

I don't know this for sure and I am sure one of the moderators might be able to reassure you, if you have sent the form off and have proof of postage and can prove you have returned the form I don't think the DWP can just stop your money.

It's not like you deliberately witheld it or sent it back late and once the form has been posted it's out of your hands. I would think that if you show you posted it in good faith them I can't see that they can stop your money for something that isn't your fault.

I don't know whether to suggest you contact Atos/DWP yourself or wait for them to contact you.

Many thanks Gordon - should i wait til Wednesday to see if its' status has changed or phone before then ?
Any idea why it hasn't / wasn't signed for ?
I thought the point of sending the form via a recorded delivery service is that it is signed for as proof of receipt ?
The Royal Mail customer service representative was very un-helpful to say the least.

Madcatwoman - thanks for the info/ help advice - most appreciated . I have the basic proof of posting recorded delivery receipt so am hoping that will suffice.
Im just un-sure of how to prceed next?
Do i wait for Atos to contact me or do i contact them.
My hands are very arthritic & phoning is hard for me --- could my Wife who is my carer ; phone for me on my behalf ?