Why my phone doesn't charge with locked screen?

Good morning everyone, my G22, widely advertised as a fully repairable phone, has a serious problem which makes it impossible to use. After about 2 weeks from purchase it began stopping charging every time the screen was locked, both from me and from the automatic timeout. The problem appears with other cables and AC adapters, in provvisory mode, but not when the phone is off. After many tries and a hard reset I had no alternative than sending it to the repair center, where they couldn't fix it because it was a software problem. The seller (official HMD store) refuses to take it back and give me a refund, as they should do if they're not able to fix their phone. Anyone who had this same problem and solved it?

Personally I strongly recommend not to buy these phones anymore and iFixit should think twice before sponsorizing this garbage.