There's no official iTunes customer support number in circulation. However there's a way to get phone help by requesting a call-back.
1. Follow the link to open the general Apple Get Support panel.
2. Select iTunes & Apple Music option > iTunes Store
3. From the list of suggested, most popular topics pick the topic of your interest or click on "Other iTunes Store Topics". Depending on how urgent your issue is, you will be presented with various contact options. Usually selecting something like "Purchases, Billing & Redemption" > "Unrecognized charge" will give you Chat Support and a Call-back (immediate or scheduled).
4. If you are presented with the "Talk to Apple Support Now" option, click on it and provide your contact information.