wum2012
Do you have proof of delivery when you returned the ESA50 to Maximus?
Did the letter from the DWP asking why you had not returned the ESA50 include a date you had to respond by? Is this the date that you mention in your post?
When did you write back to the DWP?
When did you receive the P45?
As you have received a P45 this means that the DWP have closed your ESA claim and it is likely that you will have to request a Mandatory Reconsideration in order to overturn this Decision. See the ESA Appeal guide for how to do this and the section also contains template letters that you can use.
www.benefitsandwork.co.uk/help-for-claimants/esa1 You have made a good start by enclosing a copy of your ESA50 with your reply to the DWP, if you have proof of delivery then you need to send them a
copy of this as well.
Was this a new claim or the reassessment of a existing claim?
Gordon