DigiDelivery Receiving Failure

[tosem]

I read the forum, yet I found no solution to my problem, so I'd be obliged if someone could clear things for me.
When I try to download a delivery, the client downloads for some time, then obviously gets disconnected (the colour bars go to orange, then red, then disappear completely). When the client reconnects, it doesn't resume the download from where it was cut off (as it should, according to the manual), but every time it starts from the beginning. The file size is 230 MB. I only succeeded downloading it when I left the computer running overnight - apparently the connection gets better at night and it downloaded the file without being disconnected. However, since I'd be receiving a lot more files like that in the future, it's quite inconvenient for me to leave the computer running every time I have a delivery, so what could be the problem? I could live with the long download time and the disconnecting if the client resumed the download from where it left off. The thing that bugs me is the starting from the beginning. I read that you should have a static IP address to send a delivery - does that apply for the receiver as well (since my IP address is dynamic, and the for a static I'd have to pay almost double).