I have a doubt about skyrim dlcs

I think its like g2a

GMG had a big issue with Witcher 3, where they were selling it cheaper than anyone else and the publisher got upset and said that GMG wasn't authorized to be selling those keys.

Everyone kind of assumed they fell off the back of a Russian truck, but nobody ever actually proved anything.

GMG has had a lot of issues. Ignoring the fact that they've been accused by several publishers of selling unlicensed keys, they're known for rude support, not offering refunds or replacements for games they mislabeled the platform on, not offering support for games past the first week of purchase (despite it not having been in their ToS for the longest time that they did such), not offering support for purchases if you indicate any part of the purchase was used for an account other than your own (including that of a family member) (which also wasn't originally in the ToS, and is a legally dubious policy), and I believe one or two other things.

Do note that I've personally had game keys "expire", so don't ever let GMG keys sit unused past the first week of purchase, or you do run that risk. Other than that and making sure not to indicate in your support tickets that any part of your purchase was used for someone else [including, for example, for trading], it's unlikely you'll have any real issues with the site, though their support will still potentially be extremely abrasive and unhelpful in general. :X

As far as the unlicensed keys, I was under the impression that they did make sure to resolve the Witcher 3 thing adequately, and that no other developer has really taken GMG to charge over their unlicensed key sales, so I don't think there actually any real risk to using GMG, at least in regard to unlicensed keys.

So in that sense, yes, keyradar does seem a bit strict- though I think that's less actual strictness, and more that they don't create unique information prompts for each since, simply labeling them as 'Licensed' 'Unlicensed' and 'Has had issues'. GMG has in fact had issues, so they get a warning prompt, even if those issues never actually ended up in long-term harm to any customers.

That bodes poorly for instant-gaming's credibility- many scam sites include paypal because including paypal is a sign of legitimacy, while making paypal difficult or impossible to use, so as to make sure users end up moving into the scam credit card payment option.
For example, one wine club scam I'm aware of always insists their paypal is temporarily down, and that you should most certainly switch to a credit card payment instead (Hint: Their paypal is never actually up.)
That wine club's reviews are fairly similar to HIPAY's. :X