Changing flights

I booked our flights early in the year then my husband got a new job. Tried to change the flights by navigating the website. It kept coming up with an error notice and wouldn't let me do it. I therefore resorted to speaking to someone on the phone. She quoted mt $720 to change the flights. $300 of that was $75 each, each way on both flights. When I asked for the breakdown of the remainder she quoted me flight fares which were dearer than I had found on the Internet myself. When I queried this I was told it was more expensive to book flights by phone. I explained that I wasn't able to access the service online but was informed that I could try again online if I wanted but she couldn't hold the tickets. I booked new flights and ended up paying $150 less but in effect I have lost my two original flights and payment. She pointed out that flight prices change, as if I was a total moron, but the difference was only about $200 . How can it cost $300 for something that's done on a computer anyway? It's not like they even issue tickets like they used to . I changed my son's air aia flight for $35.... Won't be flying jetstar again, the most recent flight was delayed by 9 hours and it was a complete debacle at the airport.....having to get a bus from gate 2 to gate 4 via the construction works , waiting 15 minutes in a stairwell for the bus to come back. Yep but nah....don't think I'll bother again.

Indonesia-Denpasar (Bali)