reading sms from GSM modem

Hi, any expert out there can help. i wanna read out my GSM modem message. but i'm not sure how to retieve it out from the GSM modem.. any comment?

here is my code:
With serialport
.PortName = "COM10"
.BaudRate = "115200"
.StopBits = IO.Ports.StopBits.One
.DataBits = 8
.Parity = IO.Ports.Parity.None
.ReadBufferSize = 10000
.ReadTimeout = 1000
.WriteBufferSize = 10000
.WriteTimeout = 10000
.RtsEnable = True

.Open()
.DiscardOutBuffer()
'for reading sms

atcCommand = "AT+CMGL=all" 'to read from inbox
.Write(atcCommand + vbCrLf) 'execute command on buffer

"below the code, i onli can read out "at+cmgl=all" which i dont need it.. i need the message from the GSM modem."

TextBox1.Text = .ReadExisting

End With