I like AltServices, and regularly buy from them - the good news. The bad news of late I am told is that shipping from the U.K. via the Royal Mail and USPS option has become erratic. Spent the past few days on the phone with USPS trying to find a set of limbs - ordered a month ago and no luck. FYI, the tracking number supplied by AltServices is a customs number, it cannot be used to "actually" track a package here or there.
USPS said stuff can sit at Customs for up to a month. So, in the event you do buy from the folks at AltServices, and I encourage you to do so, insist on a shipping method which does allow "actually" tracking from start to finish. That's my advice anyway, in the meantime I will be waiting for several layers of governmental folks to do their jobs. My son may outgrow his limbs before he even gets them!