Charities must have a lawful basis to contact you and must honour your preferences under UK data protection rules. If they are not doing so, you have three escalating options:
- Ask the charity to stop, or to reduce contact to once a year. Most have a preference centre.
- Fundraising Preference Service — a free service that requires a named charity to stop contacting you within 28 days.
- Information Commissioner’s Office — if a charity keeps contacting you after you have objected, this is a data-protection matter.
Volume of post is not a sign of a badly run charity in itself, but the cost does show up in the accounts under fundraising expenditure — which you can check on any profile.