Reibun
。。。

That's fine. They've been selling overpriced, substanceless brand goods and raking in obscene profits all this time. Going forward, they should just do their best to run an honest business.

Literal

Fine [feminine-のよ]. Until-now substance-lacking brand-goods [obj-を] highly selling-forced-[and-て] excessive-profit [obj-を] devoured [progressive-てきたんだから]. From-now-on greatly conscientious business [to-に] devote-[conditional-ば] good [feminine-んだわ].

暴利をむさぼる 'to devour excessive profits / to profiteer' is a vivid set phrase (暴利 'excessive profit' + むさぼる 'to devour greedily'). 実のない 'substanceless / lacking substance' modifies ブランド品. せいぜい 'at most / to the best of one's ability' here has a condescending 'they should just' tone. Strong feminine speech with のよ and んだわ endings.