4inkjets.com Customer Service Issues

I recently bought two sets of inkjet cartridges for my Canon MP [redacted] printer. The cost was approximately $[redacted]. My husband suggested returning them due to the high price, so I reached out to customer service for guidance. I followed the detailed instructions provided to return the items in their unopened box, and I have confirmation that the package was picked up by the post office on March 9th, [redacted]. The return policy mentioned a timeframe of 7 to 15 days for processing, but it has now been over 30 days. I emailed the customer service representative who initially helped me with the returns over two weeks ago, but I am yet to receive a response. Despite multiple attempts to call and leaving three voicemails, I have not received a callback.