I think your problem is not with the font (it seems to work) but with the way you have produced the html. Odd divisions inside words across lines or pages suggests that the html looks something like:
Code:
<p>The following word will break across lines/pages on some readers <span>W</span><span>o</span><span>r</span><span>d</span>.</p>
If this is the case, you should find another way of converting the Word document into html. You could try to copy paste the word document directly into sigils wysiwyg-editor - that can create other trouble, but it is a possibility.
((
The src-statement is the path of the font files
inside the epub file - so this is the files you just added (mangal and mangalb), so it is important the the filenames in the src-statements are actually the same as the ones you've added.
But it seems to be correct since it is displaying on the reader. ))