Online shoppers now have longer to cancel orders while complaints calls should be cheaper, under laws that took effect on Friday 13 June 2014.
The cooling-off period for an online order has been extended to 14 calendar days from seven working days.
Shoppers can claim a full refund during this period without having to give a reason for the cancellation.
Companies must also offer phone lines that cost no more than a local call for customer inquiries or complaints.
The rules see the final stage of implementation of the EU Consumer Rights Directive.
Charged for complaining
The regulations cover a number of areas of consumer rights, including the introduction of a cooling-off period for digital music, films and books for the first time.
Retailers must not supply the content within the 14-day cancellation period unless the consumer has given their express consent to this happening, and the consumer must also acknowledge that once the download starts they will lose their right to cancel.
Any extra charges for those buying with a debit or credit card must be clear from the start, the rules state.
The rules should bring an end to calls that can cost up to 41p a minute, for those trying to make a complaint.
Companies will still be able to use phone numbers that carry higher charge rates when customers are purchasing goods or services, but not when they call afterwards to raise questions or complaints about them.