Yes you can return a stock provided it hasn`t been styled or the excess lace [which comes on all systems and has to be trimmed off] hasn`t been removed. I copied / pasted this from the ` FAQ` link :
Q: What is your guarantee?
A: Customer Satisfaction Policy for Custom and Inventory Hair Pieces

Toplace will remake or refund any custom system that is not made to your original specifications. Toplace will fully refund the cost of a stock unit if it doesn't meet the customer's needs. The customer will have 30 days upon receipt of the unit to return the unit to Toplace. The unit must be returned to us in the same condition in which it was received by the customer. It cannot be cut-in, washed or worn. The client is responsible for mailing the unit back and will apply insurance or any other tracking method desired.