I bought 5 random steam keys for £5, but upon receiving them I changed my mind and wanted a refund (note that I did not redeem the codes). I talked with tech support and in under 10 minutes I received my full refund (minus the buyer protection, but that's in the T&Cs of the service) without any hassle and with great help from Michal. I have been using Kinguin for more than 6 years and I always am extremely happy with their system and support.