Ok so I brought old Gmail accounts from several sellers , some on this forum. I log in with residential proxies and adspower, but in 2-3 days someone changed password and 2fa code so I can't use accounts anymore and this happened to me a lot of times. But if I change password and 2fa same day account would be disabled, or even than also someone change password. So what's the best option to secure Gmail accounts I bought. When I tell seller that accounts are hacked he says I have 24 hours guarantee. So I want to secure accounts immediately after I log in, what is the best way, recovery email, phone number or something else?