Hi @mihaisuciu84 ,
The above is good advice. In addition, you may want to refer to the below reference for a further explanation of things. If you are worried that multiple failed credit checks will make your situation worse, the below reference gives options which do not require a credit check and it claims there are such options also for EE which you should get independently confirmed (e.g. in an online chat which you save) before you rely on that information.
If you decide to go with EE, it would be better to do it online so that you have the ability to cancel in the cooling off period. Personally, I would recommend to purchase your device separately (to avoid issues we see on this forum in getting devices unlocked etc.) and take a SIM-only contract. Many people would disagree with this personal opinion. Good luck!
https://kenstechtips.com/index.php/mobile-phone-credit-check
