Mobile data contract

I refer to my case number J03963, this is now nearly 10 months waiting for answers. After they agree to their mistake they ask me for my Bank statement which I send to them on them on the 28th September 2020. After a lot of phone call and a lot of emails to follow up they said to me on the 27th January 2021 that they will investigate with the finance department why I did not receive my refund on the 5th December 2020. Today I received an email from Mondo's that they will escalate this case. Is that possible?????? They add to my reference another number J03963/97QL1P. How can they now escalate after I had to send my Bank statements 5 months ago for refund. Really this is poor service, when I had to pay the debit me with incorrect amount, now I struggle to get a refund for nearly 7 months