U-Haul Moving & Storage of South End

I wish I could give this business 0 stars, or perhaps a negative number. I had boxes purchased at U-​Haul that I did not use, about $ 60 worth. I brought them back to this location (where I had transacted other business), and was supposed to get a refund. Instead I was charged again for the same boxes. 3 weeks later, and nearly 4 HOURS spent in various calls to various people at U-​Haul and I still have not received the initial refund or, the now necessary second refund. I’m still out over $ 100 after having spent over $ 3,500 with U-​Haul in my cross-​state move. U-​Haul has confirmed that the double refund is due and states it has already performed the refund, but my bank has not received the credit. And now the store manager at this location, Matthew Lastra, refuses to take my calls or return my messages.
This location NEVER answers their phone. It either gets answered by another location or by someone at a remote office. Obviously their sales staff is incompetent as they are unable complete a refund correctly.
The main «customer service» number for U-​Haul has not done them any favors either.