A decrease in internet speed when in Bridge Mode is atypical, if not non-existing.
Help Desk people not always tell the truth about the more technical matters, due to lack of expertise.
It really makes sense to dig a little deeper into your problem. First of all the following.
- what is the speed of your Ziggo subscription?
- what Ziggo Modem/Router do you have?
- what Router is connected tot the Zigge Modem/Router in Bridge?
- did you test the speed over a cabled connection?
In order to determine the speed of the Internet Connection an UTP cabled test is required. It should give results that match the speed Ziggo promises.
Use this test with great reputation: http://www.dslreports.com/speedtest
If the results are disappointing, it is necessary to test the speed, with the cable of the testSystem directly connected to the Ziggo Modem/Router, replacing your own Router temporarily..
By doing so, you can outrule a possible problem with your own network equipment.