OP weren't you selling gifting accounts...?
Anyway, technically, everything that goes on this forum is subject to bans.
For example, buying/selling accounts is specifically against Riot's TOS so if they find out, your newly purchased account can be locked forever.
But as we all know, that is probably the most conducted business on this forum.
As far as exploiting the RAF system is concerned, Riot has already announced that it will implement a new system to fight it - RAF 3.0.
No one knows what they will do to discourage the current abuse or how they identify the abusers.
But the nature of it is already against TOS, so by engaging in it, you are submitting yourself to possible future punishments.
No seller can guarantee 0% ban rate, nor should a seller be responsible for bans.
That is because there is no completely ban-risk free RAF exploitation.
Yes, you can make accounts through different VPNs and implement other steps to ensure "safety," but as noted in Riot's memo concerning RAF change, 100+ referrals at this point is virtually impossible and just that fact alone can give a reasonable suspicion to suspect that it's an exploitation.
If you didn't think it that far, it's your fault, not anyone else's.
You actively sought and engaged in a bannable offense, so you'll pay the price for it.
You want your account to be ban-free? Then don't do anything that's against Riot's TOS.
If you do, just know that you are putting your accounts at risk for bans.
Now, it is very unfortunate that your account became subject to a ban.
I think you were just extremely unlucky.
While I appreciate you coming forth with your account being banned and to warn us that it does happen, I do not think your title, message, and big bold capped letters were either necessary or appropriate.
That's just my 2 cents.