Bitmain did not accept my BTC

I tried to buy a S19 miner from Bitmain and transfer my BTC.

Nope, this is the mail I got from them:

"Sorry to tell you that your balance payment was Intercepted by our Risk Monitoring Dept.
Please provide your BTC wallet, we will refund to you.
By the way, you can try to pay us from other wallet, thanks
I think they don’t know what Fungibility mean. They did refund my coins.

By the way they use old 1### BTC addresses. So this cost me about 4$ in fee.

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