ESA backdated eight years

After many complaints letters and the CAB getting involved the DWP insisted I was on the correct amount of ESA. I'm on a low income insurance 'income protection scheme' through my employer after I squash my spine. I've gone through a tribunal to stay in the ESA support group which I won in 2012 but no one still picked up the problem. I've been on the contributions based ESA for the last 8 years and doubt I'll every return to work because of the problems I have with my spine. I'm still employed by my company which the ESA assessor finds hard to believe, next time I'm going to take a pay slip. Because my wage are so low I get a top up of ESA , after 2012 I gave up on getting the correct amount believing the DWP were correct. Last month I got a telephone call from the DWP saying we haven't been paying you the correct amount of ESA for the last eight years. At first I was delighted and then angry because it coursed a lot of hardship as I had a mortgage to pay. I've now had all the back dated money which was just under £10,000, I've paid a chunk of my mortgage, I've also had to inform the tax man as I'm on the cusp of having to pay tax. Do I have any legal rights for compensation for their incompetence...?

Thanks Gordon, Yes they thought my Income protection scheme was my pension, for the last eight years they have asked for my wage slips which show IPS on them. Just about to start complaint to DWP, Thanks for the info.