Your experience may differ but in mine the local PEA issues a reminder and that is followed up by a visit by the meter reader.
If the above does not result in payment of arrears then at start of next billing/month the actual meter is removed.
Arrears owed plus a 100 bht reconnect/install is the only remedy unless properly negotiated.
Most PEA offices I have entered also have a counter that tries to accommodate customers who have financial stresses.