Issue with getting educational loan statements

Hey guys, had a quick search of the forums but couldn't find anything relating specifically to an issue me and my wife are dealing with at the moment. I had an account here years ago, but forgot the details :/ please excuse the brand new account.

The issue:

My wife has education loans from high school and University in Thailand. We both work full time in specialized professions abroad, so my wife has been making a concerted effort to get her Uni loans repaid with voluntary monthly payments over the past 4 years. 

The problem is, while she's been making the payments, she hadn't really paid attention to the total amount owing, figuring the account would close when the balance had been paid. The bank (krungthai) doesn't send out statements either. To keep it short, there's a very real possibility that the account is very close to being paid off, or we've actually overpaid depending on the interest calculations (which we can't figure out because they don't send out statements). We've been trying pretty desperately to get this information, but we end up chasing our own tails, constantly getting bounced between call centers and on 2 separate occasions have just been told to go through our old receipts to figure out how much we've paid! There's over 8 years of receipts to go through considering she's in her 30's; some are at home with family, all the current ones we have records of, but it still doesn't help considering we don't even have an accurate number of the total loan amount left with the voluntary repayments/how the interest is applied. Not to mention we can't cross check the deposit amounts without an account summary. The only thing we have from the online portal is the yearly payment scheme, no other info. Getting family members involved to physically go to the bank has been met with the same kind of treatment. For whatever reason, they just don't want to release any kind of transaction or account summary.

Does anyone here have any experience in dealing with this kind of thing? I did a cursory search, but nothing came up with higher education loans specifically. Any idea how we can go about resolving this? We won't be going back to thailand for over a year, so sorting it out in person isn't possible.

Is it time to lawyer up? Would they be able to compel the banks to hand over a transaction summary?

Thanks in advance for any advice.