I was training my Clefairy till lvl 99 and then i used Move relearner to teach Cosmic Power , but when clefairy turn Clefable the cosmic Power disapeared and now im [hecked] cause Clefable does not learn it. 

What can i do?

Hello @Squallff8. My apologies for the inconvenience.

 

Clefable is unable to learn Cosmic Power from the move relearner because it does not learn Cosmic Power via level-up. The Move Relearner only offers moves a Pokémon can learn through leveling up.

However, you can teach your Clefable Cosmic Power through the use of the Pre-Evolution tutor inside any Daycare at the cost of 10k. This NPC, as the name implies, teaches your Pokémon moves that only its pre-evolution could learn and since Clefairy is able to learn Cosmic Power through level up, then this tutor will teach Clefable Cosmic Power.

To unlock the Daycares, you'll need to defeat Naero boss within Cerulean Cave in any difficulty, and to gain access to Cerulean Cave, check out this guide.

 

Let me know if you have further questions.