Is mightydeals.co.uk Safe?

I, like many others, purchased a £5 for £10 voucher deal to spend at the Tescos supermarket, a standard gift card which came up as "Used" at the Tescos check out (it hadn't been used). We waited at a check out for ages loaded with shopping. Tescos are not claiming any responsibility, and state that Mighty Deals shouldn't have given out their number. Mighty Deals Ltd/moneyexpert.com have already had complaints upheld against them by the UK's Advertising Standards Authority and others have complained to Trading Standards and had problems with them, and the company has lied to customers about their own Terms & Conditions, and the terms of this offer. They refunded me £5, upon sending a letter of complaint. I will never trust this site again, and consider it highly incompetent or worse. More details of other's experiences of that are here: ***** They send a lot of emails, the deals are repetitive and were never that great anyway. Daily Deals sites generally are full of "deals" that are not much better than you can expect to pay anyway.