Yes, AirAsia is near impossible to get a live person, unless you go in person. I have also tried to cancel a booking. Not gonna happen. Change, sure. For a fee of course. Cancel... I don't even think that option is available on their website or app.
Honestly, it depends on a lot. If you are travelling now, you are stuck with it. If you are not traveling, I would get a new one as soon as possible. Some countries will give more leeway than others. Make sure you have your driver's license with you.
You could get the multi entry visa to start with. That would give you 6 to 9 months of no worries. You WOULD need to leave Thailand at least 2 times. Maybe that will give you enough time to figure out a better option. You technically can't work on any tourist visa (including Elite).
We are talking about people who come here, maybe have a condo rented for a year, and are bouncing/running out and back into the country after a day or 2, every couple of months. Some countries allow longer stays, but most countries expect you to leave at some point if you are a tourist. And if you are staying in a resort for 5 months, you are living at that resort.
You can get a 6 month multi entry tourist visa, or a retirement type visa for longer stays, which is what immigration was telling the OP.
Tourism means exploring the country. If you only show up at one address, that is not tourism. I myself have been using Thailand as a base for exploring SE Asia, and am exploring Thailand as well. My passport is full of country stamps.
When I leave, sometimes I am gone weeks at a time, but even I am waiting for that warning now. But I am soon heading back home for a good while.
Basically, whatever you are doing, to them, it looks like you are residing in Thailand, not touring Thailand.