The ones we use (from China) never supply a tracking number voluntarily.

If there is a delay or you otherwise question it then they will.

So there is always a number just that they never tell until asked.

We had a bit of a problem recently where an order was shipped in two separate boxes each with its own tracking number. They left over there at the same time but did not arrive here together. We received one and after a few more days had elapsed we queried it with them and they provided a tracking number. When we checked it said it had cleared customs in Sydney and had been passed to AP for delivery. But after yet a few more days when it still did not show we queried them again.

Turns out that it had been rejected by Sydney customs and returned to sender. We don't know why just yet (may never know). Anyway they received it back, repackaged it all and resent it. So now its in transit again with yet another tracking number. Still none the wiser as to why it was rejected by customs. Bit odd this one.