Outstanding documents or delay tactics?

Good day

I'm extremely annoyed at the level of service currently received from Zest. Submitted claim on 08/11/2019. On the 13th I was informed that there are missing documents. The very same day I submitted the documents and received confirmation thereof. I called on Monday 25/11/2019 to hear the status and spoke with a consultant, I think her name was Kashiefa. According to her the docs were still outstanding, eventually she found the email I sent on the 13th. Then on the 27th November I receive yet another email stating that my documents are outstanding. Can someone please let me know what is going on, it's really not even such a large amount for these delay tactics. Policy ***