Why can't I respond to an answer that was posted on my other question? Something wrong with the site?

I don't even know where to begin.  I am on the Next plan and I wasn't eligible for an upgrade unless I paid my account up to 12 months (I've only had the next plan for 6 months).  So I made a payment online 9/12 and received a confirmation email and text.  I went into the store on 9/13 to pre order

I'm currently living in the US for a few months and I would like to buy the Samsung Galaxy S8 up here, because it is cheaper. So my question is, can I use the phone I bought with no problems in the Netherlands with a dutch Carrier?

I've combed the internet and this site for an answer but not finding anything definitive. We did the Samsung BOGO (that required opening a new line) and I'm trying to keep my old number on the new phone.  Maintaining the new line/number is no problem, I would just like to use that number on another