deleting payment method

Hello

I am facing the problem when I am trying to delete payment method but instant of deleting that method it is adding one more line item in the system

There is some of payment method where ranking order is not yet defined which and I am trying to delete those line item system tell me to make all required enter and when I am giving the ranking and delete it, instant of deleting it adding line item in it can some body explain me what I can do for that

My concern is to delete payment method please help me on that

Thanks

Ashish