All calls to premium rate telephone numbers are made up of two parts:
1. Service Charge
This is what Customer Calls have charged you to use the service.
2. Access Charge
This is what your phone company has charged you for connecting to the service and is not charged by Customer Calls Ltd. This is generally around 50p per minute for mobile users (up to 73p per minute) and 12p for landline users.
Customer Calls Ltd. has no control over the access charges that are added to your phone bill and as such you should contact your phone company for a refund of this charge.
You can read more about access charges, and find out the access charge for your provider, here: https://www.ofcom.org.uk/phones-telecoms-and-internet/advice-for-consumers/costs-and-billing/how-much-does-a-phone-call-really-cost