Why i am not getting my message signal as output ?

This is my code for Am demodulation.I am not getting my signal "y" as output.why i am not getting ?

clear all;
clc;
Fs = 6000;
fc=1000;
f_del=100;
fm=500;
t1=0:1/Fs:1-1/Fs;
Am=2;
Ac=5;
x1=cos(2*pi*(fc+f_del)*t1);
y=cos(2*pi*fm*t1);
z1=x.*y;
a1=z1.*x1*Ac;
y3=cos(2*pi*f_del*t1);

  lpFilt = designfilt('lowpassfir', 'PassbandFrequency', 0.1667,...
           'StopbandFrequency', 0.2167, 'PassbandRipple', 0.02, ...
           'StopbandAttenuation', 85, 'DesignMethod', 'kaiserwin');
dataout1=filter(lpFilt,a1);
DCB=dsp.DCBlocker('Algorithm','FIR','Length', 100);
demodout1=step(DCB,dataout1');  %%  demodout1= y.*cos(2*pi*f_del*t)=y.*y3
demodout2=(demodout1)'./y3;

output should be "y" but not coming...

[Ankit]

Line 12: x is not defined. Is it x1 or x?

z1=x.*y;

[per isakson]

I got the error

Undefined function or variable 'x'.
Error in cssm (line 12)
z1=x.*y; 

then I replaced x by x1 in line 12 and the code run happily to the end

>> whos y x1
  Name      Size              Bytes  Class     Attributes
  x1        1x6000            48000  double              
  y         1x6000            48000  double     

The variable y was defined