Several have me stumped:
18D Getting the feel of things (7) _ _ _ _ _ N _
(possibly "sensing"?)
21A One goes to the bank for it (5)
4D No answer (6) _ E _ I _ L
(possibly "redial"?)
13D Mercy makes on look big (7) _ U _ _ _ _ _
15D Noisy rumour (6) R _ _ _ _ _
17D Region without hills, lacking beauty (5)
_ L _ I _