Section 76 (1) notice

[InCourt]

If i recieved a S76(1) Enforcement notice in January saying
cheque acc balance £700
unplanned overdrawn Balance £400
(not sure if they should be correctly denoted as a minus figure, but they are a minus figure)

then several months later the account still accrues charges and interest and in April i recieve another one having not drawn from the account or used it saying
cheque acc balance £1000
unplanned overdrawn balance £700

Is this usual to issue two notices for the same thing with a still accruing defecit?