"Complete Savings" scheme

Yes, it seems to be legitimate sharp practice.

Completesavings is great when it works. You can get your £15 monthly subscription back by buying something from your linked retailer (in my case Debenhams, however in the last few days they seem to have allowed you to make the purchase from any of their retailers).

However recently only a few of my cashbacks are automatically being creditted to me. When you ask customer sevices to deal with this they seem to be incapable of doing so. They ask for details that you cannot supply as the retailer has not given them to you. As if that isn't bad enough, recently they have been reclaiming legitimately paid cashbacks and again you have to turn cartwheels to get customer services to deal with it. They blame some other company who apparently deal with the cashbacks even though the responsibility is theirs. Their conduct is becoming dubious and is leaving them open to accusations of dishonesty.

I am now going to cancel my membership as it really isn't worth the bother.

Since my previous post I have now managed to get Completesavings to manually pay my missing automatic cashback claims. They now seem to be doing this much more efficiently.
Since joining a year ago my cashbacks have now totalled more than £400. I even got £100 cashback on a new TV even though the price was the cheapest in the UK.
I get my monthly £15 fee cancelled out by my £15 monthly bonus. All I have to do is to buy something that I need anyway, like a shirt, from Debenham's using the free Click and Collect service.
So it works well but you have to be vigilant and be prepared to hassle them when things go wrong. Try it, it works.

I purchased a train ticket and at some point while filling in my payment details etc I ticked a box which meant I was agreeing to PAY £15 every MONTH to get saving on my online purchases (the only box I remember ticking was at the end and I assumed it was agreeing to the terms and conditions of purchasing a train ticket!).... Why would I expect to be asked to sign up to paying £15 every month while purchasing a train ticket? It was completely hidden within the process of filling in my details and paying for the ticket (you obviously have to put in your card details to purchase it). The only reference to this company was right at the end where it flashed up something like, "thank you for signing up to complete savings, you could save every month on your online purchases". I received an email a little later with my "membership number" (What membership number? I thought).... I had to go onto their website to find out what the hell had I signed up for! I looked into it only to find that they would be taking £15 from my bank account EVERY month, so I then had to cancel my membership.... What a scam... I had no idea I'd signed up for anything, I just wouldn't , I cannot afford to pay £15 a month for anything.