Don't switch from CPC > oCPM, just dupe the ad.
Weird to not get traffic with oCPM. What is your oCPM bid?
In terms of cost, if you have to bid $2.50 USD it generally suggests that the demo is expensive... Facebook has crazy moments every once and a while but if click costs for specific targets are staying high, there's a reason for it.
Maybe some other advertiser is muscling you out?
Thanks again Zeno.
I created a new campaign with different target group. CPC - $0.18.
It doesn't bring me any conversion though and there was a huge bounce rate.
I will probably create an ad for more of a CPA product soon.