Overtons.com Customer Service Issues

On June 7, [redacted], I bought two items totaling $[redacted].53. Unfortunately, the main item was incorrect, so I requested a return. They provided a label, mistakenly for the second item. After contacting them, they sent the correct label, but by then, I decided to return both items as I no longer needed them. On July 1, I received a credit of $[redacted].79 without any explanation, only noticing the refund on my credit card statement. I suspect they may have deducted the cost of shipping the items back, which was their mistake, leaving me with $52.74 owed. Despite attempting to reach customer service, I have been on hold for 35 minutes without success as "all agents are (always) busy."