What was the matter with you?
这句话本身就是陈述语序!在宾语从句中不需再变语序.
当疑问词在句子作主语时,特殊疑问句用陈述语序.本句What 作主语
如果你还不懂的话,不妨记住,一下几句在宾语从句在中语序不变：
What's wrong?
What's the matter?
What happened?
也包括它们用上不同的时态,语序都不变.