I hate when people insist on helping me

I know that sounds terrible. I know I should be grateful for when people help me. And for the most part, I am. I love that the people I work with will ask if I need help if I’m lifting something heavy or just seem like I need help. And if I ask, I know they will help me. But there’s one older gentleman who will not even ask and will just insist on doing things to “help” me. I was carrying a box today and he motioned for me to give it to him. I said “oh it’s okay. I got it this time. Thank you.” But he just kept insisting and there wasn’t a way for me to get away because he was standing where I needed to walk. So I had to hand it to him, despite it actually hindering me as it took longer and I lose my momentum. This sort of thing happens all the time. It really slows me down and I hate how he won’t just let me say no thank you. I hope I don’t sound rude and ungrateful 😞 he’s very nice and helpful but sometimes I just want to do things myself.