Help with multiplication tables?!!?

I still havent learned my times 4,6,7,8,9,and 12 tables and my mom is really mad and all if my friends have cell phones but she says I can't get a cell phone until I learn my multiplication tables but I try and try and try but I have Ben working on them for about 7 years now and I still can't get them I have an extremely small memory and When I learn all of them except like 5 of them its like my brain reaches a stoping point and I learn one of the five but then I had forgotten another one it goes on like that until I get so frustrated and I give up then I forget them all again and have to start over my mom doesn't understand my stress and frustration if you have advice for me and my mom or for my learning the tables please help!