Toys R us - Need refund in cash

I bought for my daughter a Caylee holiday camper, on the 9th October 2023 it was on display on a special for R699.90. Had to add AA batteries for this camper requested by classier and also display on box aswel.

When we open the box and assemble this camper we realize that this part where the batteries needed to be installed was hollow and could not fitted any batteries.
The next day on the 10th of October 2023 we took it back to the store, this store are allocated at south coast mall at Shelly beach , we ask the toy to be exchanged,
We have open 4 off the same items and all these was also faulty.
Store manager said they will lay complaint to the supplier.
And will refund me..
Problem became I could not gave them te receipt because I went swimming with it in my pocket.
But showed them my bank statement and transactions made to them.
They said they can't give me cash back reason I can't give them the receipt.
And give me give voucher instead.
My daughter saved her money for this camper and feel not fair the her not getting her cash back. And feel we are now forced to buy from toy R US. Now
Is this fair and can this be handled on better way?