Hathway — Multiple unnecessary calls torturing me

I am not happy with their service and i told them clearly i dont want their connection any more. i have taken some other connection and i am happy with that. but these ### sales representatives are repeatedly calling me every day asking me if i want to recharge, giving some stupid offers. i am getting irritated by their numerous calls during my working hours and they are even calling me on sundays and irritating me. they are so immature . please take necessary action on them