Absolutely do NOT give 50K/month and if she was asking for that amount. Run, do not walk, away as fast as you can. Delete all contact information, block, never talk with her again. She will try again with the next guy.
At least someone tried to address the actual question! For the OP obviously almost no one here has dealt with money orders for awhile. She just needs to find out why it can't be cashed...and if she can't overcome that you need to call the company and see what your options are for verifying it was not cashed or how to cancel it, or have it returned to you.
I opened Bangkok Bank and Kasikorn accounts on the same day, 20 meters from each other (not in Bangkok). Just try another branch. Each branch seems to have their own rules.