Ignore data from serial

I am collecting from the serial port the instantaneous values of current and voltage, however because the reading is to fast sometimes Matlab gives me incorrect values that I want to ignore. I will try to explain.

When I receive normal data I have about 24 points per sin, however when I receive incorrect data I have less than 24 points per sinu so the frequency of the signal will not be 50Hz (20ms) like is supposed to.

Is there any solution for me to try to ignore all the data from this "wrong" sinu, and continue reading??

Help would be appreciated.

clear all  
close all 
clc

delete(instrfind({'Port'},{'COM3'}));

s = serial('COM3','BaudRate', 115200);

fopen(s);

x= zeros(1,2);
MAX = 256;

t=0;
n=1;
c=1;

while (c<10),
    while(n<=MAX), 

    x=fscanf(s,'%d,%d');

    if length(x) ==2, 
        if x(1) >= 1024 || x(1) <= 200,
             continue
        end

     data1(n,c) = x(1);
     data2(n,c) = x(2);

   if n<MAX 
   t(n+1) = t(n)+ 20e-3/24;  %here the 24 is the number of points per sinu, if someone know who to make this value change depending on the sinu it would be great, because sometimes is 23 another times 24. 

   end 
   n = n+1; 

    end;
    end;

    c = c+1;

   figure(1);
   plot(data1);
   figure(2);
   plot(data2);
   figure(3);
   plot(t,data1);

end  
fclose(s)

After I use another program to see the collected data and after to do another calculations like fft and so on.

This is a link for you to see my data and what happens to the sinu wave

http://www.editgrid.com/user/pd.gomes89/Voltage_signal

The error does not occur always in the same positions of the vector.

I would like to share my .mat file but I don't know how to do it.

Thank you.