Maybe I will try again.......
I just checked further in their terms and conditions I did not see Serbia on exclusion list?
"b. not to be a resident of Afghanistan, Angola, Bulgaria, Bahamas, Botswana, China, Colombia, Costa Rica, Czech Republic, Algeria, Ecuador, Egypt, Eritrea, Spain, Ethiopia, Faroe Islands, France, French Guiana, Ghana, Greenland, Guadeloupe, Greece, Guam, Guinea-Bissau, Hong Kong, Haiti, Iraq, Iran, Jordan, Democratic People's Republic of Korea, Kuwait, Sri Lanka, Libya, Saint Martin (French part), Myanmar, Martinique, Mexico, Philippines, Pakistan, Puerto Rico, Portugal, Réunion, Russia, Saudi Arabia, Sudan, Singapore, Slovenia, Somalia, South Sudan, Syrian Arab Republic, Turkmenistan, Tunisia, Turkey, Trinidad and Tobago, United States Minor Outlying Islands, United States, Uzbekistan, Venezuela, US Virgin Islands, Yemen, Zimbabwe, American Samoa, Congo, Cambodia, Panama, Samoa, Brazil, Switzerland, Mongolia (please be aware of particular country exclusions for Casino - Games - Live Casino, Poker and Bingo)"
*But under casino games is this (Serbia on list):
"access to some Games may be restricted in the following countries: Albania, Antigua and Barbuda, Argentina, Bahamas, Belgium, Bulgaria, Burma, Canada, Cape Verde Islands, China, Cook Islands, Croatia, Cuba, Cyprus, Germany, Ghana, Gibraltar, Greece, Guinea, Guinea-Bissau, Iceland, India, Indonesia, Israel, Ivory Coast, Japan, Laos, Liberia, Libya, Lithuania, Luxembourg, Macau, Macedonia, Malaysia, Mauritania, Mexico, Monaco, Morocco, Nauru, Nigeria, Niue, Norway, Poland, Portugal, Russia, Senegal, Serbia, Sierra Leone, South Africa, South Korea, Somalia, Sudan, Switzerland, Taiwan, Thailand, Turkmenistan, Uzbekistan, and Zimbabwe."