Hello @Leandro2121 ,
Welcome to the community,
Have you tried upgrading via the EE App? You should be able to do so, if you are eligible and have reached the minimum term of your contract.
To contact EE customer service dial 150 from your mobile phone or ring customer service for free using Skype or another phone: +44 800 079 8586 or +44 800 956 6000.
