I have had a very bad reaction to the product

I had ordered the Slimbetti weight loss product. On receipt I started taking it and got the very severe diarrhea. I reduced the tablets but then started with stomach cramps that have me doubled over. I called them to ask if we can please cancel the contract due to this but the do not have a cancellation policy and are not prepared to assist. I have a full 5 months left on this and have barely taken half o the 1st month. I am asking them to please cancel the last 5 months due to this situation.