Refuse to allow to catch up? (3)
I believe the answer is:
ban
'refuse to allow' is the definition.
(to ban is to forbid)
'catch up?' is the wordplay.
'catch' becomes 'nab' (nab can mean to capture or arrest).
'up?' is a reversal indicator (I've seen 'upped' mean this (in down clue, made to go up)).
'nab' back-to-front is 'BAN'.
'to' is the link.
(Other definitions for ban that I've seen before include "'Forbid, prohibit (3)'" , "outlaw" , "Stop" , "Censor or proscribe" , "Embargo" .)