How to get an answer from the interkassa?

Question

Payment systems

Hello!
For example, I have an index.php file that contains a submit form:

<form name="payment" method="post" action="https://sci.interkassa.com/" accept-charset="UTF-8">
<input type="hidden" name="ik_co_id" value="51237daa8f2a2d8413000000"/>
<input type="hidden" name="ik_pm_no" value="ID_4233"/>
<input type="hidden" name="ik_am" value="1.44"/>
<input type="hidden" name="ik_desc" value="Payment Description"/>
<input type="submit" value="Pay">
</form>

After clicking buy, the client is transferred to the interkassa, he successfully pays
and is transferred to my site mysite.ru/success
I want to receive data from the interkassa after successful payment on the mysite.ru/success page
and send the order to the site admin panel.
Actually, the question is how to get this data + payment status in php?
That is, there will be something like this
<?php
Get data
if (the payment secret key matches) {
Enter data into the admin panel
} else {
echo "Error";
}

Answer 1

The religion does not allow to read documentation?
https://www.interkassa.com/documentation-api/

Answer 2

perhaps my answer is no longer relevant, but for example I could not figure it out myself, I wrote to technical support through the official group in contact.
I attached screenshots and everything was fixed for me)
now I’m already reading the information on the link above and I understand much more))
so don’t be afraid to ask technical support too)