University doesn't seem to reimburse interview costs

A few months ago, I visited a university for a tenure-track interview in computer science. Before my visit, I received an interview policy sheet from HR stating all the usual things (economy flight fare, etc). After the interview, I was told by HR that I need to mail them my original receipts, which I did instantly upon my return home.

After a few weeks, I inquired regarding the reimbursement and was told that my receipts hadn't been received yet. However, the tracking service (I had used registered mail) did indicate that they had been delivered and, after a second inquiry, HR confirmed that they should have been received at their university but aren't to be found anywhere and reiterated that they need the original receipts to reimburse me.

This was 3 weeks ago and my subsequent enquiries have been met with silence. I did receive a job offer but, also having received another offer, accepted a position elsewhere and informed the university about my decision.

Is there anything I can/should do about this?

To be frank, the university is overseas and taking the probably very expensive legal route is not an option for me. That said, the interview expenses are in the range of 1.2k USD and thus non-negligible for me.