It's impossible to answer this question definitively. The data, or part of it, may or may not have already been overwritten. You should download and try DMDE Free Edition. Read the installation instructions first.

If a file cannot be recovered in the DMDE Free Edition (or it is damaged after recovery) the same will occur in the paid versions. DMDE paid versions are capable of recovering the same files. The only difference is that paid versions can recover all found files in one go, as well as restore the directory structure presented in the free version.

It depends on the problem. There is the manual. E.g.: Data Recovery.

You are using the Free Edition: you may recover files from the current panel only (currently visible files in the opened directory, up to 4000 at a time). Make sure not to mark directories or files in other directories (use the context menu, e.g.). Or buy a license and make sure you are using a licensed copy.

Yes, paid editions recover directory structure shown in the tree panel. However, you should first try file recovery with the Free Edition since file contents may be damaged (see the next question).

Make sure you have tried the most recent software version. Run Full Scan, try opening different volumes and reconstructing file system and data recovery. If you still have problems then files are probably overwritten after removal (for some reason) or file system is seriously damaged. Not overwritten files of known types may still be recovered using signatures without original names and directory structure (see the directory "Raw Search Files by Signatures"). If DMDE does not support the necessary file types you may try other software or seek help from specialists. It may also be worth trying the most recent beta version for the newest features and fixes.

No, the main rule of data recovery is to not write anything to the damaged disk. Automatic fixes may cause irreversable data loss. Human study is required before any such fixes. Anyway you need another medium to keep a backup copy if your data have some value. DMDE is data recovery software and not a file system repair tool.

If you have a backup copy, you can try the built-in OS tools, such as chkdsk on Windows and fsck on Linux; they fix FS errors (however data deletion is possible).

Make sure you completed the order and specified the correct email address. Check your spam/unwanted mail folders. Request your license key. If you don't get any response then your mail server is blocking incoming messages / not working, in such a case send us feedback providing your order details and another contact address.

Make sure you are using an original unmodified software copy. Download the software again from the official site, unpack it, launch it and enter your license key.

Request your login if your license support is not expired.

You may find upgrades and discounts available for you in your personal site section (restore login).