Give every price a scope.
Define the service, currency, tax treatment, included quantity, valid date and permitted options. Keep exceptions separate and name who may approve them.
Block unknown numbers.
Kai checks every outgoing price against the approved list. If a number is missing or the request combines services in an unknown way, the message stops and reaches you.
If a price cannot be verified, silence is safer than a confident guess.
Record every change.
When you update a price through Telegram, Kai confirms the new rule and uses it from that point onward. Old quotes remain visible in the customer history.