Where can I cancel? – Six Pack in 30 Days - 6 Pack Review

This is a great app, easy to use and effective! Only problem here, there is nowhere for me to cancel the premium account I signed up for! I hate it when apps make it difficult to cancel. I would absolutely change the star rating on this review if someone could help me out ?
Review by samd12359 on Six Pack in 30 Days - 6 Pack.