Iphone 8

How to stop excess payment for Itunes?

Every month i am receiving a message from Itunes in which they told me i have to pay 8.99 lv. Everything started before 6 months when i did not know that when i dwonload music in my computer ,which is with windows sistem, and transferred it to my phone iphone 8 with a usb cabel it will be immediately transferred to Apple Music and I will be charged a subscription. I went to the apple store in my town and when they helped me to see where are my subscriptions,there were no subscriptions, and a month later they kept coming and crediting me to the account. I called Apple's international number, but within 10 minutes no one picked up my phone and I gave up. Please! Help me!