My guess is that you would be getting an error message on the radio if you had the original. If you decide to keep the car, you might want to consider doing the 2009.5 instrument cluster upgrade to get the messages and the controls back. That is for another day.
The dinging is a warning that something is not right. The most likely item is that the trunk cover is not in place (or not being sensed). Looking into the trunk from the rear, look to the right and you will see the plastic side panel with the trunk light on it. You will also see the spot where the trunk cover hooks into place. In that spot you sill see a switch that gets pushed in when the cover is in place. That is how the folding top module senses the cover is in position. Problems in this area would be:-
- Someone checked the hydraulic fluid / pump and forgot to reconnect the switch
- The switch could be faulty
- The cover might not be in position to properly depress the switch
The paper clip trick is to remove the connector from the switch and bridge the connector pins so that the folding top module thinks the cover is in place. Just for testing and whilst working on the top with the side panel out so you can get to the pump and operate the top at the same time, don't leave it like that once you have fixed the problem
As with any internet advice, especially when defeating safety features, do your own research and attempt at your own risk..... Good luck with getting it working again.