Earlier quoted context omitted.
You should be able to cite the relevant passage in the accession treaty that Poland signed to support that assertion. You can read the treaty here: https://www.europarl.europa.eu/enlargement_new/treaty/defaul... Take all the time you need. You'll find lots of specific agreements on wheat subsidies, travel restrictions, etc. But a general claim that EU courts can override Polish courts or EU law to supercede Polish la…
Poland signed the Treaty of Lisbon in 2007 together with every other member state. That’s the place you should start looking.
Hint: the reason why the structure of the EU was designed so that national parliaments would pass their own versions of laws agreed to in the EU parliament was precisely because it is the national laws that are binding. Similarly the EU courts rule on actions of the member states in the context of the EU, whether the member states are living up to their agreement. They do not directly rule on laws or override laws in the national parliaments.