Unable to enter recovery mode

I have an eBay-purchased Moto G Fast locked with a pattern from the previous owner. I've tried to enter recovery mode by holding power+volume down while the phone is powered off, but no response. Even holding that button combo for several minutes yields no result. Volume up+power and the phone boots up as normal. I've tested all the buttons separately and they all function normally, but the phone does not enter recovery mode with power+volume down as suggested online. Any advice would be appreciated!!