Welcome aboard!
I think the dealership is telling you incorrectly; it is on them to explain how to get the rebate. Here is what I find from a lot of searches...
$3000 - MOPAR MVP Select Owner Bonus Cash Offer
DETAILS:
#43CMZ This program offers eligible consumers the option of $3,000 cash allowance to be applied toward the retail purchase (Type Sale 1 or B) or lease (Type Sale L or E) of an eligible vehicle. Eligible lifetime service contract consumers that are in possession of a certificate code received from MOPAR Program compatibility is available in DealerCONNECT.
Its "cash allowance", meaning its applied to the total cost when you sign the dotted line, not a rebate/certificate. The bad news is it looks like it may only for those whom previously purchased lifetime service contracts on past FCA vehicles, so if you never did that, you are probably not eligible. But thats just my best guess. The dealership should be looking that up for you and verifying, not giving you an phone number for more info.
If I were you, I'd tell them very politely to figure out the details (your eligibility, and if not, why not), or you may be inclined to cancel the order/refuse delivery.