Walmart complaint: customer service

I had 30 small Sam’s Club soda cans that the return machine wouldn’t take. I took them into the store to report the problem. The greeter called for someone and got no response. She told me to take them to the customer service desk, that they could help me faster. I went to the customer service desk, no one was in line, one clerk. I explained the problem and I was told he didn’t do that. and sent me back to the greeter. She again called for help, this time she was told that that person was at lunch and I could wait. I decided to go back to the customer service desk and this time asked to speak to a manager. There was only a substitute manager available, he explained they were short handed. I full understand that. He also told the clerk to take the returned cans. I am a woman 82 years old, disabled with bad back and knees, this added to the pain I always have shopping, and no reason for it. Clerk should have called for assistance from the very beginning.