GGC Diamonds Washington DC

I called GGC and agreed with Jill to sell them a 10 oz Pamp gold bar at Spot Gold price. they asked me to send bar by mail to their LA office. no problem.
Call a few days later, Hello, we got the bar. thanks. but in order to authenticate the gold bar we had to drill a hole through the bar. now the bar is damaged we can pay you Spot Gold price — 4%.
WTF? no, Jill. we agreed 100% Spot, send that or return undamaged gold bar.
next day — great news, we can pay Spot –3% to you for damaged bar.
no, Jill. we agreed 100% Spot, send that or return undamaged gold bar.
next day — great news, we can pay Spot –2% to you for damaged bar.
no, Jill. we agreed 100% Spot, send that or return undamaged gold bar.
–1%? no pay what we agreed or return the bar. they paid, but still shorted me a couple of hundred dollars from what spot price we agreed initially.
AVOID.