There are multiple ways to pay, @Lucyloo0505, so if you can't access My Account, try another method.
Simplest if you actually set up a Direct Debit - Chat should be able to help with this.
Other methods also mentioned here:
https://community.talktalk.co.uk/waystopay
Gliwmaeden2, a fellow customer.
From the 29th of March our TalkTalk Community will move to peer-to-peer support and the TalkTalk team will no longer be here to support with queries. Don’t worry we still have plenty of ways to reach out if you need to speak to TalkTalk directly. For more details check out the link in the post at the top of any forum message board.
