請譯英文, THANKS!

We regret the careless mistake made by our team members and sorry for any inconvenience caused to you.

I apologise again for the inconvenience caused to you by the negligence of our group members.

If you are talking about your employees, you can change "group members" to "employees"

We are so sorry about our(our team memner's) careless mistake
and bring you lots of trouble. Please accept our apology.

or

We are so sorry about our(our team memner's) careless mistake
that make you feel trouble. Please accept our apology.