Not sure what you mean by "unavailable" in this context. However as you go on to say you can send but not receive email I can only assume that you manage your emails via email apps or email clients on your various devices.
If that is the case I would suggest that the first thing you do is try to view your Virgin Media email account directly by signing into the VM Webmail service with your VM email address and password from here. https://mail.virginmedia.com
When you get there, check to see if there are emails in your Webmail inbox that have not been downloaded to your various email apps.
One very common situation is that hackers gain access to your email account and set up an auto forward or filters so that your incoming mail gets diverted to another email account or sometimes to another folder in your VM Webmail account. Either way, it results in you not seeing those emails using your email apps.
Check whether that is happening by:
Clicking the system menu icon ☰ on the right side of the menu bar and click Settings.
Expand the E-mail options.
Select Filter Rules.
Are there any rules set up that you do not recognise? If you did not set them up then someone else did! That means a hacker/scammer has gained access to your account and may well be scamming your other online accounts such as Ebay, Amazon etc. Also, they could be setting up other online accounts using your email address.
If you find any such filter rules then you must follow all the advice here to regain control of your email account
This sounds like an issue I had a few weeks ago with one of my e-mail addresses. It was suggested that I check if my mail box was full. I checked in my webmail account but the mail box was not full.
I was also advised that VM can temporarily block an address if it thinks it has been compromised and the advice included to run scans and change passwords as well as checking e-mail addresses in webmail. I did all of these and normal service was resumed within 24 hours.
I found advice on VM e-mail support but sadly, I don't have the link. Perhaps a VIP could post the link.
Please retry again in one hour and make sure you are using the correct password to access your email from all of your devices.
If the problem continues, please call our team for help on 150 from a Virgin Media phone or mobile, or 0345 454 1111 from any other phone and select option 2. For details about how much it costs to call our team from a Virgin Media home phone, visit 8. Call costs from other networks and mobiles And vary.