My mother's email is on my PS4 account.
Lately, more precisely on December 30th, 2019 she got exactly 15 emails from the PS4 at once. Since these are all of my sales receipts that I have ever received in my "PS4 career", these can't be canceled.
It was only free stuff (such as an avatar set with 7 avatars, for each one she got an email) and never anything for a fee.
Now the question remains, why were they sent?
If it helps, on December 28th, 2019 my 1 year PS + expired and in January 20 I bought a new subscription using a voucher code.
I can't explain why you get them all at the same time. However, for games (and sometimes also accessories or DLCs) it does not matter whether bought or free of charge that this is stated as a purchase in your email (thank you for your purchase as the subject). It's just like a receipt that you can get in the store.
The respective amount (with free receipt 0.00 euro) and the date of purchase are also on it.
Yes, of course, it has to be that way. Not that you accidentally buy something and then you don't notice anything.
But I was just wondering why they were all sent off again.