The Collaborative International Dictionary of English v.0.48:

Disserviceable \Dis*serv"ice*a*ble\, a.
   Calculated to do disservice or harm; not serviceable;
   injurious; harmful; unserviceable. --Shaftesbury. --
   Dis*serv"ice*a*ble*ness, n. --Norris. --
   Dis*serv"ice*a*bly, adv.
   [1913 Webster]