It appears there is some strange character before the phone number in your custom window text. Did you maybe cut and paste from word? Anyway I think you can remove the space before the phone number in the code:
infowindowtext: '<span style="font: 12px Verdana, Arial, Helvetica, sans-serif; color: black;"><strong>Address:</strong><br />1424 W. Price Rd. Suite K<br />Brownsville, TX 78520 <br /><strong>Call Now!</strong>
The space before (956)... it isn't really a space... it is some non-readable character that is throwing off the script. You could probably delete it and add a real space.