Vodacom LTE not allowing clients to change settings after contract ended

Greetings

iam so disappointing by Vodacom business LTE division specifically, i had a contract with them for more than 24 months on 26 or more LTE devices, Huawei HG659. when the contract ended i wanted to use another network i cant, the devices are locked i cant even access them to make any changes, yet the devices are now fully paid and out of contract.

every time i would call for assistance *** etc the technician say, " they don't know how to give access"

i fill they want to keep me even when they cant give me what i need and its just so not fair for the device i already paid for.

thank you