Hey there @Josef Musil, welcome to Community!

If you’d like to change you direct debit date, simply log in to your iD Mobile app or My Account and do the following: Go to 'Billing'. On the 'Manage my Direct Debit' panel, click 'Manage my details' and then 'Change my Direct Debit payment date.

Thank you,

Tyler

I'm sorry but that doesn't work I'm tried many times 

Hey there @Josef Musil, sorry to hear that.

What happens when you try please?

Can you send a screenshot if possible?

Thank you,

Tyler