Christmas Bonus paid only once ... constant DWP errors

Apollo14LMP

I have been on IR ESA / PIP for 7 years. In that time I have received the £10.00 bonus payment once in June ! Apparently some people were not paid and the error was noted and Xmas £10.00 was received in June.

I am unsure who to contact about this and cannot get through to ESA as usual. Only noted this error whilst trying to sort out my ESA with my older daughter.

The DWP have failed on a number of occasions to calculate my occupational pension correctly - by their own error.

Bit reluctant to ask ESA for my Xmas bonus as everytime I tro to get them they mess up my claim again - that is taking off Carers Premium or misscalculate my pension.
My claim is often altered by the DWP with no input from me. Not in my favour .. 

I dont think it has anything to do with me successfully suing them ? 

Anyone else not had their Xmas bonus ??