should new cast iron have flat smooth bottom
If it's new, return it. New cast iron is uniformly awful, and your pan sounds dangerous to boot.

Look for a vintage/antique cast iron pan on ebay or Etsy or a local flea market or yard sale. You're not going to make a sow's ear into a silk purse, so start with the main ingredient you need: an older pan. If you opt to buy an older pan that is rusty and crusty, it will likely be cheap and, at the same time, your best kitchen investment ever. 

Buy some heavy-duty Easy-Off oven spray (make sure it's the heavy-duty formula), put the pan in a black plastic bag, and spray every surface of it while it's inside the bag. Seal the bag and put it in a warm place for a week. Take the pan out (wear gloves) at the end of the week, wash it down to get rid of the caked-on seasoning, and scrub it. After drying, survey what hasn't been stripped to a clean surface. Spray those areas heavy, the other areas lightly, and repeat the process. 

Old cast irons were finished by hand, and the cooking surface is amazingly smooth. Once you have stripped the pan with the oven cleaner and seasoned it, you should have a lovely cast iron pan that your great-grandchildren will inherit.