I don't know if you have ever reached out to a casino before....but it's a very hit or miss game. I have done a fair share of contacting casinos by phone, email and Facebook and it's always a mixed bag.

Even going up to a casino cashier cage you never know what you will be told.

Answers I've personally received from casino cages:

We never made this chip (when showing a picture of the chip to the cashier)
We can't sell you chips, you have to go to the tables (which the tables are closed)
We never had the Wincard Promotion at this casino (after seeing chips and the packets)
I don't have time to looks for that chip, can you come back 10 hours later

And the last time I cashed in a limited edition chip it took 20 minutes and 3 people to look it up in the book to determine if the chip was actually made at the casino.

And yes, 95% of my dealing with casinos have been positive and I always tip the cashier or dealer for helping me out.