Why try to a appear to be a nice person by donating something for the church that's not legit (a copy of a receipt, undoubtedly unusable) while at the same time sabotaging your nice person image by ensuring you'll be caught (by claiming the meal with the real, original receipt)? there is no reasoning behind all that.
I suspect that things didn't go the way TL had planned.
Could it be possible that TL was trying to time it so that she could pick up the Dinner after
OP's sister tried to redeem her (possibly invalid) copied receipt? That could explain the multiple phone calls from TL to the Deli and the 'expiration date' imposed by TL. Think about it - if OP's sister had tried to collect the Dinner using a photocopied receipt, she probably would not have been able to get it. Then TL shows up with the original receipt (and possibly the deli had no idea this was a prize, just that TL had ordered a Turkey Dinner to be picked up later) and TL goes home with the dinner. If OP's sister had tried to get a hold of TL to get the original receipt, TL would probably have ignored her until after the "deadline". I suspect that because OP's sister waited "so long" to redeem her prize, TL got nervous that she wouldn't be able to get "her" (TL's) dinner in time for her Thanksgiving Dinner. Thus TL picked up the dinner herself before OP's sister went to redeem her prize.
My apologies if this is unclear.
I agree with PP's who think that this was part of TL's plan from the beginning and that OP's sister needs to contact her church at the
very least to let them know that she didn't get her prize. (who knows, maybe this has happened before but the church wrote it off as a 'mistake'.)