If you only need one to get 10 fragments and purchase the guardian and bought 2; after getting the fragment guardian you should have an extra fragment and should be able to work on the next 10.
Did you actually open the bond when you use 10 to purchase the fragment guardian? There are two steps, purchase first and then open it like opening the holy bond.
I thought I needed two so I bought two. Then I realized that I had nine and only needed one. so no, I was not able to open the bond. I never saw the bond.
https://gyazo.com/288a477a7108bd0194d986edca992a6b
Obviously, I have one fragment to start again, but I feel I have been ripped off the guardian I should have had or at least the gold I spend on ten fragments. You really should have a warning to stop people from buying more than needed to get the bond. Moderators, please help.