Domain issues when using Memberspace

Hi

I have created a members only page on my website using MemberSpace. This means that all members must login to enter the members only page. I purchased a domain for my website which is attached and working on all parts of my website except the members page. 

When my members login to the members page the URL changes to the old site URL that was allocated to me by squarespace before I purchased my own. I have emailed squarespace and they have told me that I have set up my domain properly and they believe it may be a Memberspace issue. 

Has anyone else experienced this issue and been able to fix it?

Any help would be greatly appreciated. I go live this weekend and this looks very unprofessional! 

Could you add your site URL here so I can see your site?