Interrupt

It is possible to interrupt the service by clicking the "Interrupt" button:

It generates the following transaction parameter:

[{
    "kind":"transaction"
    "to":"KT1CxHBiCSvmXn9kXCbhPfdGDAggGG9ktQEX"
    "amount":0
    "mutez":true
    "parameter":{
        "entrypoint":"interrupt"
        "value":{
            "prim":"Unit"
        }
    }
}]

It is possible to check the corresponding transactions in the Better Call Dev indexer:

We note in the screenshot above that the smart contract pays back to the caller an amount in prorata of the session duration, as formulated in the smart contract interrupt entry point:

function get_return_tz () : tez {
    var res : int = 1 / get_rate_in_s_by_utz() * (dateofstop - now);
    return (res * 1utz)
}

entry interrupt () {
    require {
        r2: caller = opt_get(user) and now < dateofstop
    }
    effect {
        transfer (get_return_tz()) to caller;
        dateofstop  := now - read_interval;
        dateofstart := now - read_interval;
    }
}