cant put s8 in download mode

hi all,

i have a customer bought a samsung s8 in which has play store etc missing.

i cant reset the phone from inside, reset option is not high lighted.
also tried wipedata/factory reset by pressing volume up , bixy , and power button. the will not reset just reboots

also will not go in odin flash mode. even with z3x the phone just reboots.

can someone help me to flash it back to latest firmware.
can i flash through memory card?

thanks