I’m sorry to hear that, but to me the fault is mostly on you guys, and I will try to explain why, because it’s not too late to qual to split 3, and if you didn’t have make the same administrative you would have been already qual.
"Firstly we did try HK & TW before but the circuit point system seemed unfair. There is absolutely no way to qualify into VCT Ascension through hk tw premier."
You failed to go to asc, because you didn’t qualify to T2, and you fail to qualify to T2 because you fail to register in the region Riot put Mongolia in (Riot choose to put you in HKTW), this isnt an ascention point question (or maybe they are something I didn't catch).
"Asian Premier sends us to HK TW Split 2 Promo/Relo where we fight for a slot in Split 2 and an additional 15 circuit points."
Correct me if i’m wrong but I’m almost sure you never qual to promo-relo in Hong Kong ?
"Even if we get the 15 circuit points, teams coming in from hk tw split 1 already has a minimum of 30-40 points. So if we win promo/relo and split 2 there is absolutely no way of qualifying to ascension because of the circuit points system."
This is true, but this is a complain Kobold should do, it’s not really relevant to explain how you are not in T2 yet.
"That's why we decided to go into VCJ because they have no circuit points system, only one winner goes to VCT Ascension."
It's not allowed to go to JP for 5 Mongolian players, and about ascention you have 2 splits to qual to HKTW and if you do you would be the team with adventage, this is a problem only if you fail the 2 next promo/relo, but if you qual for split 3 or 1 you are the one that will have the advantage (And the rule will change anyway since SEA have fuse)
"Also there was a Mongolian Team (Kobolds) that was able to play in the hk tw challengers through premier. Keep in mind that HK & TW and Japan has the same 3/5 players rule."
That because Riot decided to put Mongolia in HKTW, not in Japan, in HKTW the "3/5 players rule" count Mongolian player as residential player, not in Japan
I found this tweet https://x.com/consz9/status/1824012737636073960 , this is the part where it is Riot fault, the support did answer bad, and they answer bad for one reason : Support isn’t here to answer to question related to esport, last year I reach the support to ask them « Hey, Bogota Premier is in LAS, but Colombia residency is in LAN, so is Colombia LAN or LAS ? » they where not able to answer to me. If you have question I recommand asking it to T2 tournament organisator (it is not Riot), this maybe this support ticket is only reason why you can advocate your case to Riot, but I'm not sure they will accept, maybe if Japan TO accept they may be lenient.
Now this is the part where I told you everything is not lost and I beleive you will qualify for next split. This is the liquipedia page of split 3 https://liquipedia.net/valorant/VCL/2024/Southeast_Asia/Split_3 this is your region and this is the only region you can qual, and as you can see they are 3 spot that isnt given, that because this 3 places will be awarded in the next Premier split, you just have to register in the SEA Premier in next act, and be top 3, and you would be a part of T2, you can and you will do it guys.
tldr ; The only region you are allowed to play is Hong Kong Taiwan (Now South East Asia), and thats where come all your problem, you will qual if you go to SEA premier. If you need any help concerning the T3 (especially with the restructuration of APAC everything may be a little bit more complex) dont hesitate to reach me on discord, I’m pretty avaliable and I would love to help you guys since the problem is mostly adminitrativen, . (I know the mecanism on T3 because I make a tons of data on it, especially in SEA where I try to keep track of roster nationality)
Bonus : Now SEA have fused all together and become THAT STACK, you are letgitimate to talk about « What part of T2 Mongolia should be », based on your unique position, you are legitimate to ask Riot if Mongolia can be a part of 1 other region, or multiple T2 region (Taiwan player can play in T2 in both SEA and China) SEA is best for ping ATM, Japan lack of player, KR might be closer in term of ping, but that would mean Riot can find a way to let you access to KR sever and you might even have a better ping than HK, to me China could be a perfect match, because the region is still young and a little bit weak, and if Riot create a server in China that is accessible in Mongolia (Probably Tianjin ?), you guys could finally start to play with a good ping, also, since they are a server only for Far East Russia (Not optimal for Siberia), maybe you could negociate the creation of a Server in Mongolia for Siberian player