Dealer could be bluffing you. The only delays i’m aware of is the 2 Series GC given quotes until Jan 2021 the same time you’ve ordered and Feb/Mar if ordered now.
Ordered my 3 Series in mid July. Got a updated 2 days ago from production that it has started to take its shape with added features. Have you been provided with a order number? If not, get one off them and have a look for yourself on the Live Chat.