The time that it takes to get your refund could depend on your cc company. The one time that i filed a charge back, my cc company granted me a refund temporary refund right away while they investigate the dispute.
This was my experience as well, with both Visa and Mastercard (not RM purchases). Especially if you're a good customer, they'll do everything they can to help you but in my case they made it very clear that it was a temporary chargeback that could be reversed if the merchant disputed it by providing proof that the customer (me) was wrong. But I was also told I would not be charged any interest on the purchase amount while the dispute was open.
I can somewhat see RM customer service getting frustrated with callers and issues but why get rude with people? It's the company that's at fault, not the customer. Seems really unprofessional.