Translation:My mom calls me on the phone when I am bathing.
That's correct and in this case, "điện" actually means "to call", at least it's part of "gọi điện". Southern Vietnamese speakers often use "điện" to mean "to call" which is similar to how English has adopted "to phone" though in the case of Vietnamese the word "điện" means electricity. The term for telephone was adopted from the Japanese coinage (which Korea and China also adopted). Electric + speech.
"Mẹ tôi gọi điện cho tôi khi tôi đang tắm." THIS IS WHAT I ENTERED AND IS EXACTLY AS SPOKEN IN THE LESSON THAT LEAD ME HERE. WHY IS THIS TAKING LONGER THAN A YEAR TO CORRECT? YES, I KNOW I AM SHOUTING BUT I FREQUENT SENTENCE DISCUSSION IN THE MAIN DISCUSSION AREA TO GET A SNEAK PREVIEW OF LESSONS AND I HOPE OTHERS DO THE SAME AND SEE THIS ALL CAPS DEAL SO THEY CAN AVOID FRUSTRATIONS OF BEING CORRECTED FOR MISTAKES OF DUOLINGO OF LONG STANDING.
"SHOWER WITH THOẠI" IS MY Mnemonic DEVICE TO REMEMBER TO ADD THE WORD NEXT TIME I DON'T HEAR IT...