Even if you pay, there is a chance that you won't get any decryption key. After all, customer service is not exactly what these guys are up to, as most of their customers don't want to deal with them in the future again.
Word on the street is that the dudes keep their word for better or worst. You pay up on time, your files get decrypted. You pay late by 1 minute or don't pay at all and you're screwed, it just uninstalls itself and leaves you with a bunch of encrypted files.