I have been getting esa for a few years, I had a person come to see

my a few months back, then i received a letter they wanted to know if i had any savings money if anything had changed so i sent it back with the correct information, now i received this does this mean, that they are going to pay me a lump sum of 3434.40 as they have underpaid me, or is that what they have paid me all the years, or do i have to pay it back, im so confused it has another attachment with other stuff on