Laxative tips?

I have a really bad case of back up in my intestines. My doc said up to 15 lbs Could be in me. I’ve been hospitalized a few times now for the pain in my stomach because of how full it always is I go to the bathroom around once a week which is terrible since I eat normal foods 3 times a day at the least. I’ve done laxatives but they couldn’t even get past it. Please does anyone have any ideas? I’ve tried a lot but are there any foods that could maybe help me go a lot in one day to clense me? Any info or tips would help. Thank you so much!