You can still read your conversations. On a paid plan, new messages pause until your monthly limit resets, or you can move to a higher plan. Each plan also has a short-term cap over a rolling window of a few hours, so a heavy burst can pause you briefly even with monthly allowance left; the usage page shows when it resets. The free trial is a one-time allowance that does not reset: once it is used, pick a plan to keep chatting.