WNDAP360 with WC7520 controller disconnects clients atleast 4 times

Hi Team,

we have WC 7520 controller and 2 WNDAP 360 Accesspoints. with firmware updated from controller. we are facing disconnection issues, almost 4-5 times a day. we have raised a ticket with netgear support (26829028) on 5/5/2016. the issue is still pending. this is happening on windows 7 with Dell  2520, 3446, Hp 440, Lenovo G580,480,570 Series Laptops.
 

Controller:

Firmware Version 2.5.0.39
Controller Uptime 1 days, 16 hours, 35 mins, 9 secs
Last Reboot Thu Jul 14 00:12:40 2016
Last Configuration Change Fri Jul 15 16:39:50 2016
Last Channel Allocation Thu Jul 14 23:30:09 2016
Last Admin Login Fri Jul 15 16:47:48 2016

can someone help resolve this issue
 

wireless card information:

Name [00000002] Dell Wireless 1704 802.11b/g/n (2.4GHz)
Adapter Type Ethernet 802.3
Product Type Dell Wireless 1704 802.11b/g/n (2.4GHz)
Installed Yes
PNP Device ID PCI\VEN_14E4&DEV_4365&SUBSYS_00161028&REV_01\4&1F3081F3&0&00E3
Last Reset 14-Jul-16 10:47 AM
Index 2
Service Name BCM43XX
IP Address
IP Subnet
Default IP Gateway
DHCP Enabled Yes
DHCP Server
DHCP Lease Expires 15-Jul-16 12:50 AM
DHCP Lease Obtained 14-Jul-16 1:10 PM
MAC Address ?F8:2F:A8:C7:1D:4D?
Memory Address 0xF7CF8000-0xF7CFFFFF
IRQ Channel IRQ 19
Driver c:\windows\system32\drivers\bcmwl63a.sys (6.30.59.26, 6.51 MB (6,824,520 bytes), 25-Nov-14 7:33 AM)

Name [00000011] Broadcom 802.11n Network Adapter
Adapter Type Ethernet 802.3
Product Type Broadcom 802.11n Network Adapter
Installed Yes
PNP Device ID PCI\VEN_14E4&DEV_4727&SUBSYS_051B14E4&REV_01\4&23872EB&0&00E1
Last Reset 11/21/2014 1:34 PM
Index 11
Service Name BCM43XX
IP Address
IP Subnet
Default IP Gateway
DHCP Enabled Yes
DHCP Server
DHCP Lease Expires
DHCP Lease Obtained
MAC Address E4:D5:3D:83:01:4D
Memory Address 0xE0400000-0xE04FFFFF
IRQ Channel IRQ 17
Driver c:\windows\system32\drivers\bcmwl664.sys (5.100.82.15, 4.50 MB (4,716,608 bytes), 11/12/2014 4:32 PM)

Name [00000014] Dell Wireless 1704 802.11b/g/n (2.4GHz)
Adapter Type Ethernet 802.3
Product Type Dell Wireless 1704 802.11b/g/n (2.4GHz)
Installed Yes
PNP Device ID PCI\VEN_14E4&DEV_4365&SUBSYS_00161028&REV_01\4&4C74C6&0&00E2
Last Reset
Index 14
Service Name BCM43XX
IP Address
IP Subnet
Default IP Gateway
DHCP Enabled Yes
DHCP Server
DHCP Lease Expires
DHCP Lease Obtained
MAC Address 90:48:9A:F6:8C:7B
Memory Address 0xF7900000-0xF79FFFFF
IRQ Channel IRQ 18
Driver c:\windows\system32\drivers\bcmwl664.sys (6.30.223.99, 8.66 MB (9,082,064 bytes), 10/28/2014 6:16 PM)