Funeral cover - top up - misleading

I took out a funeral policy 6 months ago with Old Mutual (parents cover) for my father and father-in-law. I took an amount without really knowing how much a funeral costs but the amount was substantial so i didn't think i needed to worry. I have just recently done an exercise to determine how much is actually necessary and the amount is too low but not by that much. I called Old Mutual and spoke to a charming lady but she didn't sound like she was sure about what she was advising. She quoted one amount for the "top up"cover and then said no, it was a different price. She seemed a bit flustered and there was a lot of uncer*****y. After all that, i was told i could top up my cover at an additional premium. Now in my opinion the words "top up" logically mean topping up the existing policy. Only afterwards did she start explaining to me that this is actually a stand alone policy and the waiting period starts from the beginnning.?! As i had made a mistake on the amount, i was willing to pay the difference in premium as a once off, but they refused. If this is the way funeral policies work i accept that but I'm just a bit annoyed that i was lead to believe that it could be done and then after the whole conversation, it was a no. I don't believe the company will be prejudiced by keeping the waiting period the same as its the same person and the same policy... ?