My service, calls and texts were working fine this morning. But in the afternoon, I went into a store & the store had bad service and I was unable to make or recieve calls and texts. I left the store and was able to call my mother and grandmother once each. My mother told me she tried to call me and text me multiple times in the store but I didn't have any missed calls or texts. Both phone calls to my mother and grandma were spotty. I'm home now and now I cannot call anyone or text anyone. I recieved some texts just now but they are from hours ago. Any idea on how to fix this? Edit: I'm not sure if this info is needed, but I have an iPhone 6 and I had payed for service in November 2018, couldn't pay in December (due to Christmas!) and got a free month for January 2019.