Please give a legit explanation why team Thailand lost two points and does not allow substitutions s

Need a good explanation why Thailand team was not allowed to have the substitutions.

It would be good if the technology has been developed to help the referee to make a fair judgment, for the players to have a chance to challenge and for the host to have a more convenient tool to manage the system.

However when the technology (in this case the request for challenge and substitution through the tablet) has and error with any reason, you cannot deny or ignore their requests. The right thing that should happen on that day is showing that you tried to fix the system or if you cannot fix at that time, you should go back to follow the original rule.

One more thing, the coach wanted to explain what was happening but the referee said he was arguing and trying to delay the match which is a serious misunderstanding.