An accumulation of jobs not done (7)
I believe the answer is:
backlog
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">an accumulation of jobs not done</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for backlog that I've seen before include "Accumulation (of work) to be dealt with" , "Work yet to be done" , "Work piled up" , "Arrear of wooden kind?" , "Go black with arrears of work" .)