On songsterr.com, sign in and open Account → Security & data → Delete my account, then confirm with I’m sure, delete my account. This works for free and Plus accounts, including accounts with active paid access.
Deleting your account ends access immediately, including the remaining paid Plus time, and does not automatically refund past payments. We delete the account only after confirming that subscription auto-renewal has stopped. If we cannot confirm this, your account is kept and an error is shown. For an App Store subscription, cancel auto-renewal in your Apple account first.
To use your remaining paid time, cancel auto-renewal and keep your account until the paid period ends. Android users can delete their account through the website. If you need help, email support@songsterr.com.