awr1946
There are several things, probably unrelated, going on here;
1) "got my emails back on VM but not on the mail app."
As advised by Graham_A for quite a while now VM require you to generate and use a separate Mail App password in email apps and clients. However, VM support staff don't seem to mention this to customers when solving their VM password issues.
Once you have generated the mail app password you should then update the password in the settings of you email app. The settings in the email app should be your VM email address and the mail app password.
2) "I’ve had an alert on my iPhone saying that there’s been a data leak and my passwords have been compromised and to change them all."
This link explains what that message actually means and what implications it has: https://surfshark.com/blog/data-leak-iphone Basically it means that an email address and password that you use to access one of your online accounts (such as eBay, Amazon, Facebook etc) has been stolen as part of a date breach. Confusingly, it does not mean that there has been a data leak at Virgin Media but the link explains that.
3) "I’ve also received a security alert from VM this morning. "
When VM send out security alerts that seems to be because they have been made aware that there is online traffic coming from your VM home network that suggests there is malware on a smart device on your home network.
Their normal advice is to run anti malware and antivirus scans on your devices. If their email of letter suggests that, then you need to follow their advice. However, if the email of letter suggests something different you should post back here for more advice.
4) "Was the call I had yesterday genuine?"
If you had previously been in touch with VM about your email account then you were lucky to get a call back from them but the call was probably genuine.
However, if this call came completely out of the blue and especially if the caller asked you to allow them to access your computer then it suggests it may have been a scam.
It might be wise to change the password again to play safe and to check that there are no unusual filter rules or auto forwarding set up in your VM webmail account,
Post back with a bit more background surrounding that call Without more details it is difficult to judge whether it was genuine or not.
I hope all this is useful.
Coenoby