There are a few possible explanations for why the channel is still able to upload videos even though it received copyright strikes and had some videos taken down. It's possible that the channel has multiple owners or channels, so even if one channel is penalized, they can still upload videos on another channel. The channel owner may be disputing the copyright claims, which could allow them to keep the videos up while the issue is being resolved. Also, there could be more infringing videos on the channel, so additional requests may need to be filed to have them taken down. If you believe that the channel is still infringing on your copyright, it's best to consult with an expert who specializes in intellectual property law to explore your options for legal action.