Should I complain ?

I yesterday received a phone call advising me that I had been underpaid ESA of £2,200 since March 2016 to date, this was after I sent a letter of complaint. However, the complaint has not been actioned. Should I insist on the complaint going further up management level, as I would like the DWP to get as many complaints as possible, or should I just drop it due to the stress/anxiety it's caused me. Any thoughts on what I should do ? (This is second complaint, the first being 2015 when CAB & MP assisted me, and I received £100 'special payment') I'm at a loss. Thank you for any of your opinions. Jane

Jane, I feel only you can decide if it's worth chasing yourself or perhaps involve someone else who knows the system. I would imagine your complaint is among a myriad of them. Have they said when you will be receiving your underpayment?