To change the credit card we must access from the Super Administrator user to the section My STEL Order > My subscription > Modify > click on the cube icon to delete the previous card and click on the option "use a new card" we enter the data and click on Gsave.
The reason for deleting the existing card is because usually if we add a new card without deleting the previous one, the previous one may remain as the default card and the correct card may not be charged.