This may sound totally screwball, but it's worth a shot because it's easy and I've found it has worked in other places: have you tried logging in with a VPN? If you don't have one, the free (excellent) Opera browser includes one.

Hello, and thank you for bringing up your concerns regarding the Live Chat feature. We understand how frustrating it can be when you're unable to get the support you need, especially as a Premium Plus member. This issue has been previously reported by another resident, and we are merging your comments to expedite the resolution. We have set this issue to tracked, and while we cannot provide an exact timeline for when it will be resolved, please know that it is on our radar. We appreciate your patience and your continued support of Second Life. Thank you for taking the time to share your experience with us.