Ahhh i misunderstood you ,
Entitlement to Contributions based ESA is dependant on National Insurance Contributions prior to claiming Benefit .
The basics are
here.
You will definitely need to see an Advice Centre since it sounds like they could looking at the possibility that an error has been made in working out your entitlement to contributory ESA.
The amounts are the same , except that with Income Related ESA .. any partner's income and savings etc will be taken into consideration as well as savings . Even if this doesn't affect you now it could do in the future , if for example you get an inheritance , or a partner earns more money.
If you already have a partner , second property , savings etc then this could have created an overpayment .Recovery of that could depend on whether it was their error or a failure to disclose info on your part.
If you have had been on ESA, had work for a while and then gone back onto ESA it is also possible that you could fall under something called Linking Rules . This is where you can go back on the same ESA that you were on if your period of work lasts either 13 weeks or 52 weeks depending on circumstances.
It is too complicated to explain on the forum , but if you get an adverse decision then read all mail from them fully and seek face to face advice .
Let us know how it goes.
Rich
"The difference between 'involvement' and 'commitment' is like an eggs-and-ham breakfast: the chicken was 'involved' - the pig was 'committed'."
