FXO port never hangup

Hello,
i have a strange problem and i hope u’ll help me solving it; here is my senario:
i’m using asterisk built on CENTOS core and for external lines i’m using TDM400P card and i configure a helpmenu application in the Extension.conf file now the problem is that sometimes when i dial to the ZAP/1 Asterisk play the Help menu sound file and then nothing happen and when i hang up and try again i recieve a busy tone again and agian even though i restart asterisk but the busy tone still appear till i restart the OS.
here is my configuration files:
for Zaptel.conf:
loadzone=us
defaultzone=us
fxsks=1,2

for Zapata.conf:
[channels]

usecallerid=yes

hidecallerid=no

callwaiting=yes

callwaitingcallerid=yes

threewaycalling=yes

transfer=yes

immediate=yes
echocancel=yes
echotraining=yes

busydetect=yes

busycount=10
subscribecontext=subcontext

context=incoming

signalling=fxs_ks

musiconhold=default

channel=>2

context=incoming

signalling=fxs_ks

musiconhold=default

channel=>1

and for Extension.conf:
[incoming]

exten=>s,1,answer()
exten=>s,2,Set(TIMEOUT(digit)=1)
exten=>s,3,background(greeting)
exten=>s,4,waitexten(5)

exten=>1,1,goto(incoming1,111,1)
exten=>2,1,dial(SIP/3010,35)
exten=>2,2,voicemail(b3010@default)
exten=>2,102,voicemail(u3010@default)
exten=>i,1,goto(incoming,s,3)
exten=>t,1,goto(incoming,s,3)

so if there is any1 have any idea about my problem or need additional info plz tell me
thank you in advance for being patient with me

hello again
in asterisk console i tried “zap restart” and i got the following:

Destroying channels and reloading zaptel configuration.
== Parsing ‘/etc/asterisk/zapata.conf’: Found
[Nov 6 15:15:02] WARNING[25938]: chan_zap.c:903 zt_open: Unable to specify channel 2: Device or resource busy
[Nov 6 15:15:02] ERROR[25938]: chan_zap.c:7157 mkintf: Unable to open channel 2: Device or resource busy
here = 0, tmp->channel = 2, channel = 2
[Nov 6 15:15:02] ERROR[25938]: chan_zap.c:10463 build_channels: Unable to register channel ‘2’
[Nov 6 15:15:02] WARNING[25938]: chan_zap.c:9761 zap_restart: Reload channels from zap config failed!

it seem that FXO port still occupied but i don’t know why
i hope this will help
waiting for response
thx