Improperly Denying Payment Due to Alleged Technical Deficiencies One common practice among ZPICs seeking to secure recoupments is to dispute Medicare billings, not on the basis of a lack of medical necessity but rather based upon alleged technical deficiencies with the billings themselves. Missing signatures, and even missing dates, have been cited on more than one occasion as grounds for payment denials. Yet, the law makes clear that, except in limited circumstances, such denials are beyond the scope of ZPIC’s authority.