I Forgot!!

i forgot that i was supposed to collect my money (owed to me) from the nursery. i paid them one month advance for january fee, but stopped sending the children halfway. so they were suppose to refund half of the fee back to me. which they promised to do so had i contacted the principal end of last month. but i forgot about it, totally. i check my phone calendar recently and i saw 1st february in bold; i don't recall anybody's birthday in february except mum's birthday towards the end and my niece's birthday few days before valentine's. so i click view, and there my reminder notes clearly stated that i was supposed to collect my dues. with technology invention to help human more efficient in handling daily chores, how can i still overlooked? oww... i'm getting old.