+ 1200 subscribers of CA among the inactive audience of FB

The task is to attract the target audience 3 weeks before the event.
Problems: Before that context advertising on Facebook brought a very weak result - about + 300 people signed at the price of 0.19 - 0.22 cents per subscription.
Goal: + 1000 subscribers for 3 weeks with the budget of 2000 UAH. Promote publications and events.
Result: +1235 CA subscribers in 3 weeks at the price of SRS from 0.08 to 0.11