Far too frustrating

What is one to do when encountering a very rare Pokémon for the first time - Blissey - and using both Razz Berry and Ultra Ball and it flees after the first toss? What is one to do with an endless stream of Pidgeys, Rattatas, and Centrets? Like I would ever spend one dime on this game.

Boyydz69 about Pokémon GO, v1.31.0