Shelwien, I don't know if it is viable considering long time established domain, but if something like encode.su.eu.org would be ok for free, reliable and without spam or any shady practices, then I can recommend this:
https://nic.eu.org/
I already run our NIC through them for years and never had a single issue. As long as encode is non-profit(as it is I believe) its great free alternative(unless that multi suffix is unacceptable). You wouldn't have to worry about expiry date anymore(among other things).