can they do this??

I was denied once because the insurance company had no proof of a co-morbidity (hypertention) And after submitting evidence of hypertention I was denied because i am on medication and according to them it is controled.  Can they do this? The policy does not say anything about co-morbidities being under control or untreated . All it says is that there needs to be proof of a condition which i provided!  So why am i still denied?

It's rare but it happens.  THe policy doensn't say anything about control, so you really should fight it.