Frazzled, make amends before cards put in post (2,4,4,3)
I believe the answer is:
at ones wits end
'frazzled' is the definition.
I know nothing about this answer so I can't tell whether this works.
'make amends before cards put in post' is the wordplay.
'make amends' becomes 'atone' (I've seen this before).
'before' means one lot of letters go next to another.
'cards put' becomes 'wits' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'post' becomes 'send' (synonyms).
'wits' inserted inside 'send' is 'switsend'.
'atone'+'switsend'='AT ONES WITS END'
Can you help me to learn more?
(Other definitions for at ones wits end that I've seen before include "at a loss" , "Unable to see a way forward when in trouble" , "Not knowing what to do next" , "Desperate" , "In a state of desperation" .)