Assume the letter is "legit" from the lawyer - by the time you made your purchase on DHG there is no logo no nothing on the photos.
One assumption is that this "lawyer" is trying to fish you, if you respond the mail then you open a can of worm - they will keep bugging you and try to prove you intentionally made the purchase - then you have to face the consequences in your country - depends on the regulation that could be vary from fines to court.
Of course this "lawyer" could be scammer as well
To keep your life simple, just ignore the mail
Hope that makes sense to you
One assumption is that this "lawyer" is trying to fish you, if you respond the mail then you open a can of worm - they will keep bugging you and try to prove you intentionally made the purchase - then you have to face the consequences in your country - depends on the regulation that could be vary from fines to court.
Of course this "lawyer" could be scammer as well
To keep your life simple, just ignore the mail
Hope that makes sense to you