Argentium silver fusing and soldering problem

[Molek]

Hello
Hope someone will have an insight into what is happening with my project. I am making an Argentium silver bangle that will feature a Tahitian pearl in the middle. The design is to have a sort of thick silver halo around the pearl (bead) which will be fixed on the halo with a wire. From the halo two fairly thick, 4mm wide, oval silver wires (more like bars) form an open cuff.
All was good for a while - I made the halo, soldered it perfectly with extra hard solder (Argentium) finished it beautifully, drilled the wholes and then proceeded to add the two wires, one at a time, on each side. And this is when everything went haywire.

The solder wouldn't flow, no matter how much I heated the piece, and when it seemed like it did flow the joint was so weak that it came off with no effort. I tried several times to no avail, and to the point where the halo got a few cracks and ended misshapen.
As a side note, I worked with the alloy a few times but on a much smaller scale and never had a problem. Duh, I even sang praises to anyone willing to listen about how amazing it is to work with Argentium (I usually work in gold, and dislike working with silver).

After I did read up on working with Argentium, I corrected my mistakes - laid the piece flat to support the fragile hot Argentium, obsessively cleaned and aligned the parts, and made sure I wait for the Argentium to air-cool before quenching. At first, I fused instead of soldered, which only worked on the remade halo and one side of the bangle. After trying to fuse the remaining side three times I decided to use solder. This time it worked for the remaining side BUT the fused side (which until this point was super strong) AND the fused joint of the halo decided to come apart. When I tried to fix that by soldering them a new crack appeared and the soldered bit came off.
I added support (only after it was clear that without it, the joints are not 'close' enough) on each side of the bars/wire part to make sure the joints are tight, but there was not much pressure to make sure the halo isn't squashed.

I am at a loss as to what to do now and thinking of switching to normal sterling as I'm 100% sure I wouldn't have this many problems with it...

I do not understand why the fused joints came apart - I thought the fusing is permanent and won't be as fragile as soldered joints??

Any suggestions will be welcome

Exhausted and clueless
Monika