Text gets corrupted on the press

I use inkscape for creating documents and I have hit few times promlems with press when releasing/printing the documents. I would love to know if others have had samekind of promlems or if I could do something differently to avoid any problems in the press in the future.

Most of the cases they have been able to print my documents fine on the press but I have had few times issues that the texts gets corrupted (becomes xxx) or the font type changes on the printable document. This is not really nice...

How do I create the file: I create document first at SVG form and then compile it to PDF document and send it forward to the press for publishing.

I have had few times now case where the press/publishing company have indicated that they are unable to print the document (text becomes xxx) and one case that the corrupted file have went to the paper all together :(

On lates incident I used fonts:
Tw Cen condenced extra bold became unreadable (just pure "xxx" after press)
Showcard gothic font style was corrupted/changed on the press.

The files have been perfectly ok (or at least I could not see anything wrong about them) when send to pressing machine/company. Have other users have had same kind of promlems and if you could solve the situation somehow? and Is there something I can do differently to avoid such a incidents to happen in the future (use different font styles? Use different document type?) or is this totally press company related issue and using inkscape has nothing to do with it? and I have been just very unlucky few times????

Publishing company says that I use weard document form (not adobe generated/supported), they are not familiar with Inkscape and they are unable to find where the rootcause of the problem is.... Should I change my scalable vector graphic program (to Corel?) or should I do something differently with inkscape?

Thank you for all your feedback, answers and opinions...