Call the Gemeindeamt in Leopoldsdorf bei Wien, to check whether they are processing the cards.
http://www.leopoldsdorf.gv.at/gemeindeamt/3683-parteienverkehr-gemeinde.html
It is possible that they might not, in which case the Bezirkshauptmannschaft in Bruck an der Leitha is your next port of call.
https://www.noe.gv.at/noe/Bruck-Leitha/Bezirkshauptmannschaft_Bruck_an_der_Leitha.html
Please also see https://www.britishinaustria.net/article-50-card/