Leftover communion wine

In my church we have now gone to both the individual cups and the common cup. Should the wine that isn't used from the common cup be put back in the wine bottle for the next service? To my surprise it is. I am having second thoughts about taking the Lord's Supper now. Not wanting to start trouble in the church. Who should I talk to? Thank You.

Wine in individual cups that were not used in the Holy Communion service can certainly be used in a future service.  That is not the case with wine that remains from usage of the common cup.  The wine that remains in that cup is to be disposed of.  Practices for disposing of wine can vary from one congregation to another.  I would direct you to contact your pastor to seek clarification about your congregation’s practice toward unused elements in the Communion service.