Service center would be your only option for items that may be in stock, but they carry very little inventory. Most likely will have to order it online. Tesla, just as with ordering their cars, is not an instant satisfaction type of company. You pretty much have to wait for anything. A new car to be ordered, service appointments and yes, online ordered accessories. I've ordered several items over the years on multiple occasions. Their average turnaround time has been between 2 and 4 weeks, even for the simple items. Speedy delivery is definitely not their strong suit.
I have the all weather mats and do like them. However found out that they just buy Weathertech mats and stick their Tesla badge on them. They are absolutely 100% identical, yet through weathertech.com, you can get them for about half the price as what Tesla charges and they promise much faster delivery. The ONLY difference is they will not have the chrome badge that says "Tesla" on them. Other than that, there is absolutely NO DIFFERENCE. They are the identical mats. So you pay around double just for that Tesla badge.
Anyway, just an option that would get them to you sooner, for around half the cost. I was pissed after purchasing mine from Tesla, only to discover Weathertech had the same mats for much less. 100% could care less that mine say Tesla in the far corner of the mats where nobody looks anyway.