From my experience knowledge and research whatever I know is that nowadays one can take credit only if the credit reflects in GSTR 2A and the credit reflects in GSTR2A only when the supplier has your GST and he pays that GST.
Now 2nd thing what your CA is saying that you need to pay GST I don't agree with that because the thing he is trying to say is that law says if a gst registered person is buying any goods from GST unregistered person then that GST registered person needs to pay GST on such purchase in RCM, but right now RCM has been postponed and no-one has to pay GST in above mentioned example.
Any which ways above mentioned example doesn't apply in your case because the supplier from whom you are purchasing for eg: car is paying GST on same so you don't need to pay it.
Also it's important to mention that since you are running some business you won't be able to claim credit of any vehicle that you have purchased for business only certain specified businesses can take credit of vehicle and since you can't claim credit of GST on vehicle you can add such GST amount on total amount of vehicle and claim depreciation in income tax.
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