Bicycle detail

The owner of the bicycle let an acquaintance take it for a ride, since he had offered his service to pick up just a block away in front of the apt complex. I had a feeling; unsure of it till i started off for my bike ride,, i had. Problems getting it to ride straight... Went. Back home after a block of short pit stops to make adjustments. Nothing worked, the day went on i said it doesnt feel right... He said there was nothing wrong with it.... But thruth is. It was swapped. For an 18 fime 29. Tired haro.... The response to where or what was done to my 29 inch. Haro mountain bike. Is nothing.... I am on a hunt for my bike. Shocked\ very. Upset. Ill find it...