Easy fix!
1. Buy a dipstick.
2. Drain the transmission ATF fluid at the sump.
3. Remove the transmission sump pan.
4. Push the new dipstick up the dipstick tube from the sump end to remove tissue back out of the top end of the tube. Clean the tube by pouring the old ATF fluid down the tube and drain into a container.
5. Replace the transmission filter.
6. Re-install the sump pan with a new seal/gasket (note the very low torque values for the sump bolts).
7. Re-fill the transmission with high quality ATF (Mercedes supplied is good) and live happily ever after.
See the end of the dipstick at the top left of the picture of my transmission with the sump pan removed. My transmission is for the C36. Yours might be a bit different.