Pretty simple question.

I went to BC T1 on Monday night with a group but we didn't manage to beat it.

On Tuesday the group with a few others beat T1 without me.

Now yesterday mostly the same group including myself grinding T2 for hours but again we're not able to defeat it.

Question is am I able to go back and complete T1 if I can find a group or am I stuck this week trying for T2 or higher because I was already in T2?

Remember I didn't defeat Cas in T1 but played T2 but wasn't able to kill ADS either.