Food Panda — Lots of deduction from invoices against agreement

Address:

Ali AL Kabab Halal Food Restaurant Malolos bulacan

We make agreement with food panda for our restaurant food delivery this year
Now food panda start to deduct lots of money from our invoices and whenever I email them and I try to reach their area manager or agent but no one answering my call and replying my text for explaining about deduction of money
I don't know who I'm going to contact and where I am going to complain about food panda
Hopefully my problem will solve here and I will get my money back that food panda deducted from my invoices
Thanks