Dear nicolicb,
Please note that Serbia is listed among the restricted countries in their Terms and Conditions, and the casino reserves the right to change their T&C, which is also stated on their website:
52. The Company reserves the right to amend Casino and Bonus Terms and Conditions, or to implement/amend any procedures, at any time without prior notice to you. Such amendments will be implemented at the discretion of Casino management and put into immediate effect. These changes will override any pre-existing Casino or Bonus Terms and Conditions.
54. The Terms and Conditions contained herein represent the complete, final and exclusive agreement between you and the Company and supersede and merge all prior agreements, representations and understandings between you and the Company with regards to playing in the Casino.
This clause emphasizes that only the terms stated in the current Terms and Conditions are valid and enforceable. Given this, unfortunately, there is nothing further that can be done in this particular case.
Feel free to check this page, where you can find online casinos that accept players from Serbia.
Thank you for your understanding.