Please help i k on a part time job to help with financial needs but i am also on jobseekers allowance but?

But now the jobcentre have contacted me and said that they have paid me to much as they qouted in a letter to me that they should give me £80 per fornight and now they are saying that it should of been under £30 per fortnight and now they say i owe £380 i dont have that kind of money i barely have the money for rent.its all legal and above board every hour i work is declared using a b7 form and the jobcentre knows that i am working 7 hours a week but they got how much they owe me wrong when i declared that i started work in october
Answer
Agree to pay them back 1 pound a week or something. they are not allowed to force you into poverty