Check yourself on Have I Been Pwned, and if you see your information have been breached, reset all your passwords.
There was a thread about HNers having a common name and firstname.lastname email addresses and getting random emails not for them..
So you can start by changing your password maybe?
I was getting Netflix account information and Uber trip receipt emails in Spanish for a while with no option to say “this is not me”.
Actually, even if it's accidental, if you do it close to when they've opened the account (when you started receiving the mails), they wouldn't lose much if any data.
Of course, that's assuming that you have no way to contact them. If you can, that might be better.
EDIT: Changed "their account" for "the account" since it could be said to be yours too since it's your email. They effectively signed you up.
Hours of my time wasted because a company doesn’t verify emails.
You should change your password to something you don't use elsewhere just to be sure they aren't attempting to log in with your actual password.
4 emails in 10 days is not excessive.
If the e-mails bother you and your account is secure, then you can just filter them into a folder and then go looking for them when you actually need to reset your password.