If Statment with Index Match

Hi

I want to write an if statement based on whether the index match statment equals a figure greater than 0 - if so then I want to use the figure if not then I want to use another formula. The current formula gives me a value error.


=INDEX(Stock!$B$5:$Y$14,IF(MATCH(TOTAL!$A$21,Stock!$A$4:$A$14,0),MATCH(TOTAL!D$7,Stock!$B$4:$Y$4,0))>0,INDEX(Stock!$B$5:$Y$14,MATCH(TOTAL!$A$21,Stock!$A$4:$A$14,0),MATCH(TOTAL!D$7,Stock!$B$4:$Y$4,0)),C21+C28-D10)

I would appreciate any advice!