Regular payment slashed (4)
I believe the answer is:
rent
This clue is a double definition.
'regular payment' is the first definition.
(rent is a kind of regular payment)
'slashed' is the second definition.
(I've seen this before)
(Other definitions for rent that I've seen before include "One due a letter" , "Payment for accommodation - that's torn it" , "Tear; lease" , "money demanded by letter" , "Tenant's fee" .)