If you do complain to PEGI you might want to quote code 9.2 as loot boxes is a way of corrupting minors and their development as well as 9.9.
9.2 Removal of Undesirable Content; Signatories shall use their best endeavours to ensure that Online Gameplay Environments are kept free of content which is illegal, offensive, racist, degrading, corrupting, threatening, obscene or might permanently impair the development of minors.
9.9 Protection of Minors; In keeping with one of the main objectives of both the PEGI and PEGI Online Systems, Signatories shall adhere to stringent standards ensuring the protection of children from any unsuitable content and behaviour associated with any Online Gameplay Environment offered by any Product aimed at children. These standards shall include, as appropriate;
the publication of warnings about the supply or display online of private email addresses
promoting responsible purchasing practices within Online Gameplay Environments where minors are concerned.