Amazon India — Regarding order of Treadmill

I ordered treadmill from Amazon on 31 oct 2021 and it was delivered to me on 3 rd of nov 2021 the order was cash on delivery I paid through cash all went well till this but after the product was delivered it’s been six days I have not received any installation however the product when I ordered was told that the installation will be done and the concerned branch will contact me within 48 hours of delivery I have tried to contact Amazon regarding this and they are just giving me multiple numbers of the brand, When I tried to contact them they just simply said that it’s not their product, I will attach all the required documents invoice copy and conversation please help me out For further details please contact me on [protected]