Why??

I loved the game so I decided to put 15 dollars on it and opened all my boxes kettles etc... Its hits me with 2 feral ghoul attacks not even 5 mins apart and kills my entire production rooms and leaves me with an astounding 7 dwellers left alive out of 88...... Wtf?! Dont waste ur time or money on this garbage

Wasted!!:/ about Fallout Shelter, v1.7.1