I wouldn't go so far as to ask you to play fair, but I would appreciate it if you could refrain from thoughtless behavior.

Literal

Fair-[adverb-に] do-[let's-う] [quot-とは] humble-say-[not-ません] [though-けど], thoughtless behavior [topic-は] honorific-stop-[receive-want-頂きたい] [polite-です] [feminine-わ].

A compound layering of extreme politeness markers. 申しません is the humble (kenjougo) negative of 言う 'to say.' おやめ頂きたい is an honorific request construction: honorific prefix お + masu-stem やめ + 頂く (humble 'receive') + たい 'want' = 'I would like to (humbly) receive your stopping' = 'please stop.' The sentence-final わ here is the emphatic feminine marker. The whole sentence layers multiple keigo devices into a hauteur-softened demand — a distinctly feminine high-register scold.