Nuna mixx car seat/adaptors

Does anyone have this travel system? We had it with my daughter and my husband has put some adaptors on the car seat today (assume they are to be clipped into the pram) and they are stuck - the pram is at my mums and I’m stressing that they are stuck stuck and we can’t remove them now and it’s screwed 🙈 baby is due in 3 weeks! Help. Thanks