Pathetic, Bad, Disgusting Service wont use again

My sister was travelling to Abu Dhabi and Online Electronic Ticket number *** . After arriving at the Airport at 07:30, we showed the Ticketing staff the online ticket and they informed us to wait for Seychelles Airline to check in, 09h30 I enquired again since our flight was 09h55, the staff told us that our ticket was Seychelles and it was supposed to start checking in anytime, when we proceeded to check in counter they could not pull out our ticket, the Supervisor only realised later after about 45 mins that we were supposed to have boarded Etihad airline and by this time it had departed. We were referred to the ticketing office where the ladies tried to help and kept calling the Seychelles airline office in Seychelles and all lines were not being answered, they also mentioned that they were not trained by Seychelles airline so they didn't know their ticketing system at all. On the 2nd of Feb I contacted the Seychelles office again and was told to pay a penalty for their mistake, there wasnt any empathy at all, all i could hear was there is nothing we can do to help! Really...anyway I ended up buying a new ticket since my sister's days were expiring. Pathetic service