Please read this topic of a user with a similar issue:
maybe your problem is the same.
We recommend you to run and test the samples in the package. and try using PHP CLI mode running the included samples standalone to find the source of the problem. Maybe your server is adding extra strings to the DOCX files when downloading or generating it.
About sending a custom template, sorry but the trial package doesn't include support for this. After you have purchased a license please contact as again and we'll check it.