After you file

I received my letter stating why there was an adjustment to my return. After the irs made their adjustment and sent the new amount to tpg. Tpg deposited only 2/3 of the refund. Tpg is holding $2,330 without any explanation. Is there any way to get ahold of anyone to find out why they are holding my funds? Unfortunately as  hard working single parent in this environment I need that money ASAP.