Hi Allan,
I am Dave, I will help you with this.
Well done for being suspicious, rest assured that is a scam, the senders address is spoofed to look like Microsoft, but it is not, Defender is and always will be free, there has been no money taken from your account and they are just trying to gain access to your bank account defaults, usually they will offer to provide you with a refund and ask for your bank account details.
You can safely ignore and bin that Email.