It is not completely clear what the situation is, but from what I deduce it seems that you are the sender and the recipient does not recognize a payment you have sent.
I guess you have verified that the accredited address
1Gouzjo9Jav1k4AmRoUJJMzidVfnMoSieS it coincides with what was supposed to pay, and that the amount coincides with the invoiced amount.
1Gouzjo9Jav1k4AmRoUJJMzidVfnMoSieS has received 0.02661900 BTC in transaction b36157a7ca9630a88d98125fca91de81f488ef7d9a60f9e57af055d4d91f7a50. This transaction has been written on blockchain more than a day ago and is confirmed. Since this is the correct address, the receiver was paid, whatever they are claiming. Second, the money has already been spent again, which means that they must be fully aware that the money arrived.
Assuming you have paid the correct address, the problem is at the end of the receiver:
Or they gave you the wrong address you paid correctly and someone else received the money (unlikely), they don't understand that they were already paid or they incorrectly represented your payment (unlikely, since you already tried to follow up with them), or they are lying to you.
You should follow up with them and firmly affirm that the address requested in question has been paid (after having verified that it was the correct address) and ask them to verify that their systems are working properly. Perhaps that will prompt you to "suddenly find your payment."
Under no circumstances send them more money, if they do not recognize that their payment has been successful and deliver their part of their agreement. Often, scammers invent meaningless excuses for you to pay even more money. If they don't recognize your payment, you may have to decide to cancel that money or sue them.