I assume that you're referring to mightydeals.co.uk (which is now discountexperts.com anyway), rather than to mightydeals.com (which is a specialist supplier to graphic designers, etc).
The site acts as a 'marketplace'. i.e. they don't actually sell anything at all themselves; they're just offering a place for traders to offer their products. As such, they're reliant upon those traders not to mislead customers in any way. However whereas, say, Amazon Marketplace is generally used by trustworthy firms, Mighty Deals tends to attract quite a few dodgy firms to its ranks. So it's unsurprising if you find that such traders are seeking to mislead potential customers.
Unlike Amazon (where you can get help easily if you've got a problem with a Marketplace trader), Mighty Deals has an appalling reputation for its level of customer support (or for the total lack of it). Nearly all of the recent reviews on TrustPilot award the site just one star
https://uk.trustpilot.com/review/mightydeals.co.uk
and every single review on Sitejabber gives them one star too
https://www.sitejabber.com/reviews/mightydeals.co.uk