A "Pashkevil" against a store: Is it permissible to use items purchased there?

Hello, dear Rabbi. This morning we shopped at a store in Beit Shemesh "***". In the afternoon, we saw posters on another street against the store, stating that it is forbidden to shop there. I am attaching the letter. What should we do? The children are asking me whether to throw away the items we bought or if it is permissible to use them?

Hello and blessings 

There is no prohibition on using what you purchased. 

[P.S. I did not find any rabbi signed on this, so for now, do not regard the leaflet as more than a 'pashkevil', meaning slander, gossip, public shaming, and discord].