So what's the solution?
WHY ISN'T MY MEMBERSHIP OVER YET?!

I have ordered a membership for exactly one year.
But today is already 27th of June, and My membership is not over yet!
Please help me.
If you got the trial first, then the actual term wouldn't have started until 7 days later.
You can check your expiration date by going to https://www.chess.com/membership
That said, all memberships are subscriptions, so if you don't cancel renewal, it will automatically renew and won't end.
https://support.chess.com/article/585-how-does-membership-renewal-work

Go to settings, and click Account/Payment. There should be a cancel button. If it renewed, you can either contact support and make them cancel it or just wait another year and then cancel it. If you cancel DURING a membership, you might get some money back but I'm not sure.

...If you cancel DURING a membership, you might get some money back but I'm not sure.
No, refunds are only given if requested.

i had golden membership but someone gifted me diamond membership for a week so that golden membership has been expired and now i havent got any membership

Ohhhh... because if u upgrade you get some money back.
Upgrades from a lower premium to higher will have a partial credit, prorated based on how much had been used, toward a brand new subscription at the higher level. If you downgrade, from higher to lower, it will extend the term of the new level, based in that same prorated amount.

i had golden membership but someone gifted me diamond membership for a week so that golden membership has been expired and now i havent got any membership
If you have a lower membership and get gifted a higher level one, it just extends your current membership. If you upgrade to take advantage of the gift, you have to downgrade at the end or the remaining amount in the account applies to the higher level and will result in a decrease in the original term.
I have ordered a membership for exactly one year.
But today is already 27th of June, and My membership is not over yet!
Please help me.