Cannot access cellular data

I have a iPhone 7 on boost mobile service. My service was working fine 2days ago and suddenly started getting an alert saying something about my device cannot access cellular data.. it asked me to update my phone, which it was and still is using the latest iOS. The alert is tied into what’s causing my phone to say I have No service. My boost service is paid and still has about 1/2 a month before my next billing cycle. I do not know what I need to do to access my cell service.. can anyone help?