Is someone using my alt email related to this platform, or am I the target of a scam attempt?

I just turned my phone on to only find out that someone has used my email (called Mercai Notify US) to attempt to sign up on here (probably as a throwaway), and suddenly I am being harassed with multiple emails "interested" in Five Nights At Freddy's keychains(?) for some reason?

I never used this platform ever and I can't find a suitable contact on the Mercari website to tell if this is true or not and it's getting late here and I am being nagged by multiple emails every 5-10 minutes and it's getting on my nerves