Just speculating, if your shares dropped to 0 and balance did not increase, then you got a payout directly.

Follow up questions:

How long were you mining?
Did you at any time stop mining?

What is your wallet address/

It's likely because rewards for a found block were distributed 7 hours ago, so I'm assuming your balance or payout has increased.

not enough balance

Well you got paid, trust me a fair amount for your share.

Yes, we might not find another block before VTC halving, the hash rate has dropped, many miners stopped mining VTC.

Yes, whatttomine is highly inaccurate, especially for coins with large difficulty swings (like VTC).

You only get paid for mining the blocks that are found by THIS pool, not for every block found on the network.

You are more or less on the right track to grasping it. The difficulty is not necessarily only split by the port (3072 vs 3073) you are mining to. The difficulty is adjusted automatically by a "feature" called vardiff , so there can be several various difficulties.

PPLNS does not go to all the returned shares at time X, but only all the returned shares that fit within the last N shares ( = network difficulty * 2). Some shares might not fit, if it took the pool more than network difficulty * 2 to find the block. See round 5 in FAQ.

Further adding... the number of shares can't be easily and accurately represented in a coin value as this is not PPS (pay per share) pool, so in theory, it's possible not all of your shares will be counted for the reward calculation. See the FAQ for reasons. Maybe later in the future, the pool operator might give some more data to help you understand past payouts, as in no of silently dropped shares or so...

Google is your best friend really, there is no way around it. But to really simplify things

blocks = make up the block chain, each block consists of transactions on the network, blocks are added to the blockchain by miners when they find a block

reward = is the coin miners get as a reward for finding / adding a block to the blockchain

hash = consider this as your mining speed, the higher your hash the more computing power you use to solve crypto puzzles that are required for finding a block

difficulty = this is the difficulty of the cryptopuzzle, the higher the difficulty the more hash power is needed to solve it. There is also variable difficulty for us on a pool like this, where we are given only parts of the puzzle to solve depending on our hash power. The lower the hashpower, the easier the parts of the entire puzzle are given to us by the pool to solve. The reward you eventually get is then relative to the difficulty of the shares (pieces of the puzzle) you solved.

Well we can't all be made to understand everything can we? :) To sum things up, the reward system this pool uses rewards loyal and consistent miners over pool hoppers that jump pools to get the quickest buck for the kilowatt. 

You guys clearly haven't done any research on how mining and rewards really work.

1. You only get rewards for participating in blocks found by this pool.

2. You DON'T get paid when this pool does not find a block.

3. Mining calculators are highly inaccurate.

4. In PPLNS reward system, you will not necessarily always be paid for every share.

5. You can't make a judgement on a short period of time in a small pool. The variance is just crazy.

6. Read the FAQ! https://poolmining.org/faq