Hey eylül250,
Thanks for using Apple Support Communities! I understand you deleted an alarm but it still went off as previously scheduled. I definitely want to make sure you're able to manage your alarms without issue, and I'm happy to help.
To start, if you haven't already done so let's restart your iPhone. Use the steps for restarting here: Restart you iPhone, iPad, or iPad touch
Let's also double check that this isn't related to a bedtime alarm. You can check that and make any necessary changes with the steps here: Use Bedtime to track your sleep on your iPhone
Thanks again, and have a great day!