Need some suggestions to fix a knife

So recently, I purchased a Yoshimitsu Blue #2 petty. Yesterday was my first day using it at work. After a few hours of work, I quickly realized the knife was bending between the heel and bolster of the knife. I could also feel, while using the knife, how short the tang was in the wa handle. The bending was not caused by cutting but wiping the blade on a towel. Currently, the only way of wiping down the blade is to place the knife between a tri-folded rag and pull back.

Does anyone have any suggestions on how to 'stiffen' up or fix the bending issue?

Not sure I understand the issue. Is the metal bending ( changing shape), or is the handle coming loose? I assume it is a Japanese style handle. If it is the later, I would remove the handle and re-attach with epoxy.

Send it back if the tang is actually bending.

Check if the handle is loose and slowly being pulled out. Some tangs are slightly bent and require expert handle skills to align properly.