Hi John,
I do sell on eBay...and some of my cables are imported to the US
Did you buy it from me? not that it matters, I have had a few fail but for the most part they are a good (not great) but good less expensive cable.
What are your errors? what speed are trying? I also have a few 'real' Siemens cables but they are not cheap
The people in HK sell them cheaper then I do but I test everyone before sending it to the customer and also replace or refund if there is an issue, have you contacted the seller?
Mark