Formed another merger, having said one wouldn't (7)
I believe the answer is:
refused
'said one wouldn't' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Perhaps you can see a link between them that I can't see?
'formed another merger' is the wordplay.
I cannot really understand how this works, but
'another' could be 're' (I've seen this in other clues) and 're' is found in the answer.
The remaining letters 'fused' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'having' is the link.
Can you help me to learn more?
(Other definitions for refused that I've seen before include "Said no (7)" , "Declined, rejected" , "Not accepted" , "turned down appeal" , "Was unwilling to accept" .)