Discount after 12 months not applied as stated in letter from KPN

Can somebody, please, comment my question here. Thank you. 

Hi @Rainmans, we deal with these topics in chronological order. Which means that it can take a couple days before one of us moderators gets to a topic. Other users can reply in the mean time. Which happened with your other topic. But when it's a question like this, other users tend to take a step back as they can't really help with that.

I've looked at your contract and such and I don't see that letter here. When did you get it?

Hi, and thanks for reply. Here is the letter received. 

I also have a hard copy somewhere. 

Thank you, @Rainmans. When did you get this e-mail and the hard copy?

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The image did work, @Rainmans, but it took a while to load. So, I removed the image from your new reply to make the topic less crowded.

What I'm seeing here is that you had a move last month, and I think that might have been the cause of this not going right. To verify that, can you tell me when you received this e-mail?

Without that information I can't further check how to fix this.

Dear @Erik_ ,

Thanks for your message.  I received 2 letters on that topic: first letter by normal post (hard copy) received somewhere in August 2023, another one by email on October 5th, 2023