Randomly apps store opened on its own

I don't use instagram so I don't know if somebody can post automatic links to items there.

If you still have questions or problems:

Refer to this document for ways to contact Apple ➞ Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone ➞ Contact Apple for support and service - Apple Support

I don't have this issue but I am wondering if you are viewing web pages that are automatically causing this to happen. Is this happening while you browse the web?