Cant see how you can call it Business ADSL, if its useless after hours
I've seen some of your posts, so let me try to explain.
The Business Account is just that, designed to be unshaped and uncapped during business hours. It's not really meant for heavy personal use, but for offices and business with multiple users during the day. The product is still unshaped and uncapped after hours, but works on a 7 day rolling window. Depending on how much your usage was and when it spiked, it will return to a full throughput once the rolling window total falls below threshold. However, it will always be running at full speed during business hours.
You can send me a PM so I can try to give you an idea of when the after hours speeds will return to full.