Fermentation Troubles..maybe?

So about three months ago i bought a Mini-brew plastic conical. I would be very happy about it if it went for the 4 batches including a cider that have fermented in it taste like im eating lego's. I tired different sanitizers both iodine based and acid with no success. Thought i may be my water so i got a charcoal filter. NO change. I keep getting chemical plastic smell and taste. i do have a control brew, a lager in a glass carboy used same water and sanitizer however its not ready and i dont really want to disturb it.

anyone got any ideas, before this thing goes in the recycling bin.

Usually the recommendation I've seen is to use diluted bleach to get rid of the plastic smell/taste in things like cooler MLT's. Let it sit in there maybe overnight and rinse it out really good afterwards. See if it still smells like plastic.