Hi web-tech.sk, it looks like your Sale has been corrupted if you cannot download it from the Premium Plugin Updates screen; looking at the screenshot you have 19 downloads remaining so it should be working.
I’ll e-mail you now an early release of the Plugin update going out today; 3.1.8 as well as re-generate your Sale so you can use Premium Plugin Updates to download updates.
Regarding the contact form, until recently cForms had been eating some enquiries and not passing them onto our Inbox. We’ve since rebuilt the forms and will be migrating to a new form enquiry system with the launch of our new site. I’m very sorry that we didn’t respond sooner.
