What part of 7 is tripping you up? And 13?
I'll bet the default answer here applies to you... pincer blades.
On 7, kill the first wave by running and sliding/attacking into blade mode for easy chopping.
When they're done, charge a pincer attack and wait for wave two -- hit them with it and just keep playing smart... parry if you can, especially if the customs group up in wave 2 or 3.
Wave 3 can be the same as wave 2 -- start with a charge pincer attack... use pincer attacks to deal high damage and knock customs back, parry if you can for instant kill.
Wave 4, you can use the polearm to clear most of it -- if you're running short on time and the gekkos won't charge? Pincer attacks!
On 13, you just need to jump and hold heavy attack to do the sawblade move. that will take out a large chunk of the screechers... then just run and avoid the hammerheads until you can kill most of the screechers... change to the sai and use the powered up emp attack to get several hits in at a time. Mix with picking up the homing missles and using those to knock them down. Use the platform areas as cover to put a buffer between you and the hammerheads if they're on your ass too much. Split them up if you can.