Paxi courier

I took my parcel to pepcell so they can courier them for me via paxi courier.. They accepted my parcel, after 6 days I was called to come and collect my parcel because its over packed, they can't courier it... They don't want to give me refund claiming that their terms and conditions doesn't allow them to take over packed stuff but they took my stuff first hand, and I ddnt sign any ts and cs nor rules of paxi courier Please help me resolve this issue