To disable IPSec you must execute the SMS Utilities UCI API rule. You may refer to this link for more information: RUT240 SMS Utilities - Teltonika Networks Wiki (teltonika-networks.com)
admin01 uci set ipsec.Jerome.enabled='0'
admin01 uci commit ipsec
admin01 -> is my router password
Jerome -> is the name of IPSec instance i created
value of 0 -> not true
uci commit ipsec -> saves config
reboot -> to reload all the services of the router
Also maybe this SMS rule will help you: RUT240 SMS Utilities - Teltonika Networks Wiki (teltonika-networks.com)
I hope it helps.