What reason did the company say for not being able to upload from Xara?
Most hosting companies will allow you to use, and give you, the FTP settings that are needed for uploading your website whether using Xara Designer or any other web site design software.
Web sites created using Xara are javascript / jQuery driven which is all handled in the viewers browser, ie no server side processing with features such as PHP and MySQL are needed.
Personally I would look for a different hosting company.
They do, when you purchased Xara Designer Pro X, you should have a domain name and 2 GB of web space included free of charge for one year, after the one year expires there is a recurring fee to continue with the web hosting.