The same was happening to me and I could not set call forwarding, I was getting the same message. Spent an hour on the phone with Rogers and they couldn't fix it. I wanted to set call forwarding while away on a business trip in the US. When I arrived in the US, I tried call forwarding again and it worked fine. However, when I came back to Canada two weeks later, I went to try and cancel call forwarding and I kept getting the same message again. Spent another hour with Rogers, they were hopeless. The call forwarding setting in Supplementary Services was showing "No number set" but the network was still forwarding. The problem is not resolved but I've found the workaround. I removed my sim card, inserted it in my partner's iPhone and it clearly showing the forwarding was set and I was able to unset it from there. So to set or unset call forwarding, stick your sim in an iPhone.
