Seller hasn't accepted offer in 16 days

I'm wondering what to do in the situation where I put an offer in on a building and they accepted the offer but had to wait 4-5 days to cancel pervious accepter offer that was lower. After the 5 days they went on religious holiday for 8 days so they could do no business. Now after being back for 4 days the seller realtor says they are dragging their feet to see if they can get more. How do I handle this? Do I just wait? Do I retract the offer? ( I would like to purchase the building). It is an investment firm who bought the building at a sheriff auction and renovated it and is selling it. Any guidance is helpful. Thank you.