Hi,
We need to know what is the IP phone you are using. If you are using a Cisco IP phone then the commands which you need are.
interface FastEthernet1/0/28
switchport access vlan 10
switchport voice vlan 50
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust cos
auto qos voip trust
Voice vlan command is only supported with Cisco IP phone.
For a non-cisco IP phone the configuration would be.
interface FastEthernet1/0/28
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport trunk allowed vlan 10,50
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust cos
auto qos voip trust
spanning-tree portfast
!
Could you please remoeve the redundant configuration and check the behavior. Also if you are using non-cisoc IP phone then you have to configure the phone in vlan 50 ( i guess that has already been done ).
Rgds,
Souvik