Buyer didn't receive the jeans..

Unfortunately, yes, you'll have to. This is why you need to ship Express :/ (Did you use Priority Flat Rate?) For all you know he could've gotten the jeans but is just telling you he didn't because he knows there's no reliable tracking. (Although Priority Flat Rate will sometimes have tracking--if you printed the label online you might try to track it through PP. Not always reliable though)

Yeah you definitely screwed yourself there. Always use tracking no matter how much it costs because if someone knows you cant track the package then they will almost certainly screw you over. I believe to use an express mail international flat rate will be $27.55 if purchased online. Jeans can fit in there. Trust me it has been done thousands of times. People stuff big size 38 True Religions in there so you can do. There are plenty of helpful guides online. Just count this as a lesson learned. Also the express mail comes with free tracking plus $100 of insurance. Also it will get to your buyer in 3-5 days. YOu cant beat that.

Unfortunately I have someone also that cliams he did not get it. Thats the risk however. He seems to be trusted looking to his feedback so I did it with the normal recorded mail option. When I do not trust it I quote just the price with tracking, but in this case It seemed not necessary. But Than the customer said he could not pay until 2 weeks because he was foreign, than after 3 weeks I had to warn him, than he paid on the last day and began already after 4 days I did not get it yet, can you give me tracking? now after a month he did still not get it. So this whole process gave me from the beginning a bad feeling of this gonna be trouble. And unfortunately I am right....

I will start an investigation and will return his money if it seems lost, because thats the risk. BUT I always mention tocustomers if it turns out that they got the package and Lie about it, they have a big problem. As powerseller I was appointed an accountmanager from ebay. And If you want to scam I will sent ny proof to the account manager and the customer is handled with. But most people are honest, so it could be that it is still in customs. So what you say itsinmyjeans is to negatively thought. It happens maybe 2 times a year that something does not get there.But it almost always show up agan. I was scammed three times in 7 years, so thats not that much. But I have in my advertisements a please ask for the shipment costs. And they are dependable of the feedbacks and specifically on the feedbacks given to customers. if someone never gives a feedback on a seller, i calculate the highest amount possible with tracking, if it seems ok, that I can do it for less. And it also depends on what I paid for it offcourse. ehen I only paid 7 euro fro an item, why should I calculate 40 euro shipment. So Than you take the risk...

Yes there  is a risk when sending to Bangkok. There is a risk sending anywhere. Always use tracking. Its the ONLY way you will be covered by paypal/ebay seller protection.

Yes only than you are protected. But As you are a business seller your goal is to sell as much as possible. And i can tell you that if you want to sell international you have to take some risks. I also use tracking as much as possible, but for some countriies thats to expensive. And those countries as thailand are interesting as you put taxes on the customer. So if you sell something for 40 euro which costed 10 euro,. in fact your profit is 30 euro - ebaycosts/paypal  costs. But if you charge 40 euro on shipment do you know how much you sell?

With your statement that the item should be back right now is not true however. When it was delivered and he was not at home at the time, he has to pick it up (but unfortunately there are lazy poistworkers that do not leave a card for pick up). In most countries you have 3 weeks for that before its sent back. So when it already took 3 weeks to arrive, which is normal to countries like that, so it could be still on its way.