Complaints about unexpected mail.
THE LIKELY EXPLANATIONS
They subscribed and forgot, which is common if the gap since signup was long They were added from another context, such as a contact form Someone else entered their address You imported a list without clear consent
CHECKING
If you use double opt-in, you have a record: the date and the confirmation.
Show it to them politely. Frequently that resolves it.
IF YOU CANNOT SHOW A RECORD
That itself is the problem. Consent you cannot evidence is a weak position.
WHAT TO DO IMMEDIATELY
Remove them, apologise briefly, and do not argue.
Someone who complains is one step from marking you as spam.
IF SEVERAL PEOPLE SAY THIS
Examine how your list was built. Something is adding people who did not choose to be added.
Common causes: a contact form feeding the marketing list, a pre-ticked box, or an import from another source.
PREVENTING IT
Double opt-in A welcome message that arrives immediately, so the subscription is fresh in mind Consistent sending, so people do not forget between messages Never adding anyone from another context
