What date is your flight, OP? MIA-LAX is still flying once per day on a 77W for now. It looks like there are two TPA-MIA flights daily, but unfortunately if you want to connect on to the 77W flight it would require a very long layover (~10 hours).

If you let us know what flights you were originally booked on, we can better help determine what options might be best depending on your wishes.