Hi, my area has just accomplished time coverage, so im gonna apply 4 it. may i know the best available promo?

Time just upgraded my router to Huawei mesh(white), but i still keep my old TP Link router(black with 4 antenna). In future if i wishes to terminate my line, do i need to return both the Huawei mesh & TP link router? Or just either one? If just one, which one should i return? Planning to sell off the extra one.