VAT registered to incorrect address

I have been receiving letters addressed to a business that has nothing to do me with for several months now. I returned the first few to sender and got nowhere, so I then opened one and established it pertained to VAT so I contacted the VAT section on HMRC livechat and spoke to someone who took all the details of the letter and ensured me it would be investigated. This was June 2024 and the letters are STILL arriving, so I am at a loss as to how to get them to stop.... does anyone know how long these things take? The company do have a different address listed on companies house so it shouldn't be that difficult to work out where they need to be sent to, surely?

Hi. If you have contacted our Helpline regarding this misdirected mail then the information would have been taken and passed over to the Department responsible for resolving this. Apologies that this hasn't yet been resolved for you. As you have alerted us to this 3 months ago then I  would recommend you contact us again on 03002003700 so that we can follow this up. Thank you .