First you haven't explained how it first started or what if anything was done before it that may have caused it. you don't need OEM bulbs. as long as you get the right bulbs they should be fine. The only issue could be the THIRD Tail/break light, (if you have one) if bulbs are gone it could be the cause. Have you had someone stand behind the car and confirm what is working? Also check the connectors in the loom for the light units.
