I tried twice and the same thing happened.
and the credits were discounted both times
Operation: Unlock
Selected model: SM-A102U
Software version: 39.8
Checking Login and Password... OK
Ballance: 21 crd.
You have 21 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-A102U
Android version: 9
PDA version: A102USQU4ASK7
CSC version: A102UOYN4ASK7
Phone version: A102USQU4ASK7
Product code: SM2A102UZKZAIO
CSC country code: USA
CSC sales code: AIO
Phone SN: RF8MC1MCK9Z
IMEI: 357644101251068
HW version: REV1.0
RF cal date: 20191219
Chip name: EXYNOS7884B
Modem board: SHANNON327
Security patch: 2019-12-01
Boot Warranty bit: 0
SIM State: NETWORK_LOCKED
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... OK
Searching server... OK
Checking server answer... OK
Executing... OK
Reading data from phone... OK
Calculating... OK
Searching server... OK
Waiting for server answer... OK
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... OK
Rebooting phone... OK
Unlock done
Operation: Unlock
Selected model: SM-A102U
Software version: 39.8
Checking Login and Password... OK
Ballance: 16 crd.
You have 16 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-A102U
Android version: 9
PDA version: A102USQU4ASK7
CSC version: A102UOYN4ASK7
Phone version: A102USQU4ASK7
Product code: SM2A102UZKZAIO
CSC country code: USA
CSC sales code: AIO
Phone SN: RF8MC1MCK9Z
IMEI: 357644101251068
HW version: REV1.0
RF cal date: 20191219
Chip name: EXYNOS7884B
Modem board: SHANNON327
Security patch: 2019-12-01
Boot Warranty bit: 0
SIM State: ABSENT
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... OK
Searching server... OK
Checking server answer... OK
Executing... OK
Reading data from phone... OK
Calculating... OK
Searching server... OK
Waiting for server answer... OK
Initialization zTool... OK
Running zTool, please wait... OK
Reading data from phone... OK
Rebooting phone... OK
Unlock done