Hidden quest done, can probably just quit after the easy part

I only downloaded this 2 days ago. When I opened the hidden quest, it suddenly changed from 3-1 to 'Achieve 3-7 within 14 days after completing 2-7'. First off, I haven't even reached 2-7 yet, and the actual time limit is only 7 days. Accumulating the amount in stage 3 is incredibly slow. I spent 2.5 days non-stop watching ads just to reach 3-5, and the 'Achieve LTV ads 2.5 quest' only got to 2.3. I seriously suspect there's a system detection issue. I kept watching the TV ad at the bottom, but it stayed at 2.3 LTV. I reported these two issues to customer service, and they directly deleted the 'Achieve LTV 2.5 quest' which hadn't even ended yet, and then cut the 'Achieve 3-7' quest down to just the time limit. I'm so mad after grinding for so many days with no rewards.