You are playing with someone you have played with irregularly, but who is a good player. On the ride to the venue, you have discussed system, including that after a NT overcall by opps, you play your NT defense system (suction). Opps have asked for an explanation of 2♠, which you gave (edit: That explanation being that partner either has clubs or diamonds and hearts). 3♣ is undiscussed by opponents (who are intermediate-advanced level players). Your 4♥ bid is pass or correct.
What's your best guess as to what's going on? What do you do now?