Adidas — Refund not initiated for return request placed a month ago

I ordered a pair of shoes from Adidas and they were delivered to me on 9th May. I placed a return request shortly after receiving the product, due to size issues.
No one came to pick up the order for about 10 days. After numerous calls to customer service, pickup was finally scheduled and the product was picked up from me on 20th May. I was then intimated by the courier service that the return was delivered to the Adidas warehouse on 23rd May.

Then another delivery partner showed up to my address asking for the product about a week after the original pickup, which made no sense. On contacting the customer service about it, they put me on hold for a long time and said that they have not received the returned product yet. On telling them that the pickup has already been done, they placed me on hold again for 10 mins and confirmed that they have indeed received the product, and that the refund will be initiated soon.

I have yet to receive a refund. After a series of calls and emails with the customer service, they oscillate between saying that the return has not been received by them or that they have received it but it is still being processed. I would urge Adidas to look into this error and issue a refund as soon as possible as the amount is not trivial.

The complete experience with the Adidas customer service team has been a nightmare. Between the extensive hold times on call and the non-availability of agents through chat, it seems that the process is highly disorganised and goes in circles, with the agents being extremely unhelpful.