Hi,
The issue must be with all the restrictions that you set in your payment method.
The way you set it, it will only display if the total weight of the products in the cart is between 0.5 and 30lb, if the total volume of the products in the cart is between 100 and 100 cm^3, if the total quantity of the products in the cart is between 1 and 10 , if the shipping method selected is the one selected in the shipping method setting.
And there is a problem with the "minimum price" field. You should remove the $ symbol from the field or it won't work properly.
I would advise to remove all these restrictions and add the ones you really need, if any, one by one, and test each time if you still see the payment method on the checkout.
That way, you know when you make a mistake.