Complex sentence: As a subplot, Stan spends most of the episode trying to return the aforementioned Margaritaville mixer; the trendy retailer Sur La Table will not accept the return because it was bought on a payment plan.
Split into simpler sentences: As a subplot, Stan spends most of the episode trying to return the aforementioned Margaritaville mixer. The trendy retailer Sur La Table will not accept the return because it was bought on a payment plan.