Soak your berries in a vinegar/water solution. 1 part vinegar to 10 parts water.
Slosh them around and let them set for around 15 minutes then drain water, pat dry and put in a container in the frig. The berries will keep longer and won’t develop mold so quickly. The vinegar kills the mold spores.
I had some strawberries last 2 weeks as well as some blackberries. I hate it when I spend the money to bring home berries and in 3 days they have mold on them!