I hv to account in google play store but i want to use only 1 account for my purchase

[Alvito]

When i want to buy with redeem gift card my sceond account show but i want to set my first account

 

[webworkings]

You would then need to change the account associated with that device to the other account on Google Play.

They should be using two separate email addresses, so you can just change the one that is used by the phone.

The phone uses the gmail account you attached to it, so just change the account/email to the one you want.