Product in form

I have 2 problems with products in my gravity form

1/ I have a form setup that has 2 products, I need them to select only one of the products, how do i stop them selecting both products?

2/ Once they click the product i have it added to a total at the end of the form, But after they submit the product is not added to the cart. How do i get the product to be added to the cart?

Got the first problem sorted just added a second product in the radio button option

Just need to sort out the total not adding to cart

Can you please clarify what you mean with total not adding to cart?

I created a form with a couple of products they would purchase, and the totals added at the end of the form, but after they submit the form the product price from the total is not added to the cart, I get the form details so the form is working its just not adding the product to the cart.

So now I have added a credit card payment link instead and that payments goes though, but my client wanted the product purchase to be added to the cart. But after doing some research I think they need to purchase an addon to make it add to cart.

Update the worldpay payment on the form is not working either the payment never went though and the form details never got sent, but went to the thank you page after they pressed submit.