Amir lavassani

I bought a brand new 2019 gmc sierra 1500 denali with 6.2L engine but after 6 month of drive i find out after 4000 km of any oil change the low engine oil alert message pop up and all the time it losed 2 to 3 litre of the oil but after so many negociate with east side dealership and gm company they said its normal for all gm products. Do u think 2 to 3 litre in 8 litre capacity is normal???