Try something like:
if {glcshm.fcpaidby} in ['V','M'] and
instr({glcshm.fcreferenc},"Apollo") = 0 and
instr({glcshm.fcreferenc},"Orbian") = 0 then "Credit Card" else
if {glcshm.fcpaidby} = 'K' and
instr({glcshm.fcreferenc},"Apollo") = 0 and
instr({glcshm.fcreferenc},"Orbian") = 0 then "Check" else
if {glcshm.fcpaidby} = 'E' and
instr({glcshm.fcreferenc},"Apollo") = 0 and
instr({glcshm.fcreferenc},"Orbian") = 0 then "EFT" else
if instr({glcshm.fcreferenc}, "Apollo") <> 0 then "APOLLO" else
if instr({glcshm.fcreferenc}, "Orbian") <> 0 then "ORBIAN" else
{glcshm.fcreferenc}
The instring function is case sensitive, so make sure that you use the case that is found in the database.
-LB