MTN Contract cancellation - Migration to prepaid

I am very upset with the information I got last night . We are due for an upgrade. We decided to cancel the contract because of the bad/no signal coverage in our area. (Bayview, Strandfontein) We have gone to the branch in CW to find out about the coverage issue & they couldn't give us any assurance that it will improve. We then went to Vodacom, Telkom & Cell C & found that Vodacom has the strongest signal hence our change.<br> We called 808 to cancel the contracts but keep our numbers to port to Vodacom. We spoke to Wilson, our ***. He informed us that it will take -+2-7 working days for the migration to prepaid. What upsets me is the fact that we will lose all our airtime, data & smses.I think that this is UNFAIR as we were billed for the airtime & it shouldn't be taken away because we PAID for it. The other thing I was told is that any data or airtime that I have bought on prepaid will also fall away. I just bought my husband R60 airtime last night because he is currently in hospital & needs to contact me & me him. I was told that this too will fall away. It seems that MTN is penalising us for cancelling our contracts by taking away our airtime that we PAID for.