ESA3 FORM Confusion!!!

Katkins

Sorry to jump on this post but I've just recieved an ESA3 form. 
It says from February 2012 to now.
Called the number and the guy said it appears they have sent the form as I'm owed money. 
I have trawled the internet and cannot find anywhere a rough idea of what I could  get.
The man I spoke to said I should be getting 4 years back pay.
Does anyone have a rough idea what I may get?
Is there a minimum/maximum weekly amount I can guess from?
I've never been owed anything. I'm reading that the average pay out is £5000.
I don't want to get my hopes up but it's hard not to! 

If it helps, I'm single, only ever claimed by myself, for myself. I have moved once and had a baby the July 2013 so obviously get CB and CTC but no maintenance from the father. 
I'd be so grateful for someone to shed some light on this. 
The internet has totally confused me! Lol! 

Many thanks in advance x

poppy123456

Hi,

ESA Support Group Income Related is an extra £16.40 per week, slightly less in previous years. This is for the Enhanced disability premium.