LAS VEGAS/NEW YORK (Reuters) – T-Mobile US on Wednesday reported a fourth-quarter boost in customer growth and offered to pay customers to switch from rival services, further escalating already intense competition in the U.S. wireless market. The No. 4 U.S. mobile operator promised payments of up to $350 to consumers who break their contract with any of its bigger rivals and switch to T-Mobile. The offer came just days after ATT Inc promised a $200 credit to T-Mobile customers who switch. While ATT also offered up to $250 for switching customers who trade in their phone, T-Mobile said it would pay up to $300 for trade-ins.