I'd say there's something amiss if the OP is not getting anything. Shouldn't have to 'fork out' much to figure out the defect. If the Ku is on the same receiver as the C but is working on Ku the receiver is OK.
Could be some switch setting?? Describe how it's wired, Switches, etc. Maybe it's just not aimed correctly????
Oh, post some pictures, we like pictures.
If it turns out the LNBF is bad, I'd go for a
Titanium C1 PLL as you've got Ku is on it's own dish.
I have recently put the Ku PLL on a dish and it's really 'peaked' performance.
"Big block' performance would be a Ortho with PLL LNB's IMHO, either single or dual band. $$$$$$
BTW