Transmission stuck in 3rd 2004 sonata
 

2004 hyundai sonata with 265000 miles. I just put a rebuilt transmission in this car five months ago less than 10000 miles on the rebuilt transmission. I took the car to a place called just for tires for an oil change. This was my first time at a new shop. I took it there yesterday morning and since last night the transmission will not shift out of 3rd gear. It bangs into reverse. I'm just wondering if this could really just be a coincidence or if this man did something to my car is there anything that I can check? This morning a friend changed the transmission oil and the filter. He told me to drive it until Sunday and if the problem persists change the solenoid? Thank you in advance for any replies.