Acceptance of cash offer through ATM?

The acceptance level of SPC shareholders to the cash offer by China National Petroleum has exceeded 90%, so a delisting is unavoidable. I have therefore decided to accept their offer. Quite a pity, I thought, it was bought for the dividend. At the price I bought, the trailing yield is about 7%.

So I have to fill up the pink form and mail it out, it has to be received no later than 28/Aug. I am wondering, why can't the acceptance be performed through ATM? Afterall, we have IPO, right subscription, EPS done through ATM. The advantage is fast and reliable. Well, I don't mind they charge me $1 or $2 for this. What do you think?