This is a scam and you can get reimbursed following the process below.
If you are a victim you should first write to Complete Save to request the payments are reimbursed. The customer services email address has been helpfully provided by Complete Save in other reviews on this page.
If unsuccessful, you can claim the funds back from your credit card provider. Credit card providers are legally obliged to reimburse unauthorised payments.
If the card provider resists then you can successfully escalate this to the financial ombudsman, which will ensure you are reimbursed and you may get additional compensation.
In any case, you should also report this to the police via the Action Fraud website, as I have done.