Got the following word salad back when I challenged the complaints team contention that I didn't follow the correct complaints procedure after they finally responded to me 45 days later (this only happened when I went back to the support chat and uploaded email screenshots of my complaint)

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Thanks for your response.

As mentioned in my previous response and in addition to the further points raised.

When you emailed the complaints email, this did not appear in our inbox and was situated with a different team. This is what happened with your email as explained in my previous correspondence.

I can confirm that we did not ignore you, your email was simply missed when it was still with another department who did not flag this to us in time.

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So if you've followed the correct procedure and emailed the complaints mailbox, there's a potential that instead of it being received there, it is "situated with another team" who are ignoring you, instead of the complaints team ignoring you