QKC price was stable when every other altcoin were continuously falling from past few months. Why is price falling now after mainnet? Is the circulating supply increased after the mainnet release?

There were a lot of rumors that QKC team has increased the circulating supply to adjust the supply mentioned in CMC. I am not sure if it was true or not but it really created the Fud and stop the price to move up before the mainnet. Secondly i think all the altcoins are moving down due to some btc big movements and QKC is one them too whose price is effected by this movement.

the team should be able to distinguish between testnet and mainnet,
maybe this is some kind of news to make QKC prices rise, but instead today is down 3%

It is a classic scenario, all coins are pumping before mainnet and when mainnet comes dump happens.
But dump here is maybe caused also by postponed token swap and people can´t use mainnbet with their tokens. 

Because they dont have original native coins and swap has not been done from ERC tokens to native QKC coins. So you cant use this "mainnet". In fact this is still testnet.

QKC BTC technical analysis [BINANCE]: https://www.publish0x.com/ta-crypto-market/qkc-btc-technical-analysis-binance-xzyezj

here the latest updates from Quarkchain
QuarkChain Testnet Mining Reward Announcement
Quarkchain successfully completed the test of several testnet versions
If you’re interested with the details of all mined blocks during the operation of the testnet, the results are listed at the same Github page: https://github.com/QuarkChain/pyquarkchain/wiki/Testnet-Mining-Result
source : https://medium.com/quarkchain-official/quarkchain-testnet-mining-reward-announcement-5111c635f0a7

i hope the swap will be happend in the near time

QKC saw huge changes in its price during last couple months unexpectedly even there is lot of talk and big expectations from this project. It is clear that token will make come back huge one once the swap news will be out in few weeks if the feedback is what is being expected. It is in fact part of the preparation of money 2020 vision that's why durability and long term goals are in eyes.

If all goes according to plan then tomorrow will take place the release of QuarkChain Core 2.0. And in a month (July 31) the swap of tokens will end. Despite unlocking part of the tokens and and the prevalence of BTC, the value of the Quarkchain fell, but he still tries to get back to your level.

As i see they unlocked some part of tokens already. How many are they going to unlock more? There only 1/5 of tokens in circulating... This makes me scary to invest