Jul 29, 2018, 20:4207/29/18
Hello, Archon!
If I understood you correctly, you have purchased Epic Summoning Bond. Please check your Items at Guardians tab and apply the Bond to receive the Guardian. Please note that you can summon Grade 2/3/4 Guardians with this Bond, not the Rank.
Please refer to this guide to learn more about the Guardians.