cannot download national geographic subscription

All,

i have subscribed to a year's subscription of national geographic in the app (the download of the app was free).

I tried to subsequently download the latest issue of the magazine, but there was an error. i clicked cancel with the thought of redownloading it. However, now the download option is gone and the only way is to buy that subscription again.

how do i download? and if i can't, is it possible for me to get a refund?

thanks for help in advance