The website still says your order is processing.

The letter of guarantee doesn’t say if you used a delay or used the default settings. The delay can be as long as 7 days, although they do say you should contact them within 2 days if you have any issues. It also says the letter is invalid if you don’t submit your letter of guarantee within that time, which is kind of shady. The proof should be valid as long as their business exists and the cryptography used to generate it hasn’t been broken. This is the problem with custodial mixers. You have counterparty risk. ETH has decentralized mixers like Tornado Cash where you don’t have to trust somebody not to scam you.
You do have the letter of guarantee. If 48 hours passes and they still don’t reply, then you can make an accusation on Altcoinstalks and hopefully the admins can tag them as scammers or flag their thread. I’m not sure what the process is on that forum.