iStore Menlyn - After purchasing a device, you are left on your own, no support from the store manager

In December 2022 I bought a new iPhone, which came with free iCare plus. To activate the iCare, I had to register online within 14 days. I did try to register but I received errors from the website. I tried several times, but in vain. I called istore call center they advised that the manager from the store (iStore Menlyn) will be able to assist. I sent the manager email to request assistance on January 09th, then January 30th, to date I haven't had any response. I feel my request is being ignored. I cannot lose the iCare benefit because of istore website that kept throwing errors.