PQP and miles purchased through accelerators are non-refundable.
While you cannot directly buy "award miles" to gain United Premier status, you can purchase through specific United programs to reach your status goals. Ways to "Buy" Status Progress united buy miles for status
Toward the end of a year or at the beginning of a new one, United often sends targeted offers to select members to "buy up" to the next status tier. These offers allow you to pay with either cash or MileagePlus miles. united buy miles for status
united.com/en/us/fly/mileageplus/whats-new.html">United credit cards to help reach these goals? Mileage Products - United Airlines united buy miles for status