No data. My data sim will not connect. Followed all instructions still no connection. Help please.

I purchased a global data sim but can't connect to browser. Have followed all instructions still no connection. Spoke to someone in America help centre but no help. I want either a connection or money back. Problem is now back in UK so if I do connect data will expire inside 30 days and I'm not traveling again until December. Please can someone help me this is so frustrating. I'm getting nowhere with emails to supplier,this is not good enough.