Debt collector letters posted to our house for someone we've never heard of

bris

Returning the letters never works.

Just open it call the number and tell them about the mix up, the letters will stop.

And no it's not an offence to open someone elses post, it's on;y an offence if you intend to use it for illegal means.

user1977

bris said:

And no it's not an offence to open someone elses post, it's only an offence if you intend to use it for illegal means.

Even that isn't an offence if it's mail which has been correctly delivered (which it is if it has the OP's address on it), open it with any intent you like - but the usual offences of fraud, theft etc may still apply depending on what you actually do afterwards.