Alternatively, maybe it's a typo. Perhaps the user meant a different model. Let me think. The USG models are typically like USG-6000 or similar. The suffixes often refer to hardware versions. But the "VHDA7Z" part is confusing. It doesn't match standard naming conventions. That might be a problem. It could be a custom build or an unauthorized firmware.
I'll search for USG6000VHDA7Z. Oh, wait, when I search that, I can't find any official results from Ubiquiti. That's concerning. Unofficial firmware or maybe a phishing site? Could be. The user might be trying to access something that's not official. But I should confirm. usg6000vhda7z download link
In that case, the correct approach is to inform the user to only use official firmware from Ubiquiti's website. Also, warn them against using unofficial sources. Maybe suggest they verify the exact firmware version they need. Perhaps they confused the version with another system. Alternatively, maybe it's a typo