bug that wont let me continue with mount

ok so im on xbox one the quest is in the saddle i have completed 2 of the 3 courses but after i got her to set up the 3rd course my horse dissapeared and he will bot reappear nomatter what i do. i have went back to the first pkace and came back reset application restarted game and when i come back and talk to seanna she says that she already set up the course but there is no horse to mount. any ideas?