Video loss and no sound

[blazincannon 0]

Hello, I'm new to the site and CCTV. I have just purchased a Swann DVR4-4400 with two cameras plus i purchased 1 extra camera.

 

Problem 1- I purchased a standalone outdoor microphone from Maplin UK wich connects via the camera power cord splitter and plugged audio phono into back of DVR. Sound was fine but after a short while it seems to die, it hum's a little then crackles and dies. If i try again later it will work again for a short while...What could be happening?

 

Problem 2- It has 720P resolution but only offers 4 days continuous recording unless i lower resolution to 960H then i would get the 30 days i was promised by the salesman! (feel a bit miss led). Anyway, When i lower the resolution to 960H and it reboots it then suffers video loss and i can't seem to get it to work on 960H if i require 30+ recording, It will only work when i put it back to 720P, Any ideas what i may be doing wrong?, cheers.