OfferUp review: Incorrect order

I opened a app called OfferUp to sell my HP office jet pro online. for 100. the first inquiry. to buy only wants to use ZELLE... he lied about a deposit of 350. to update my app to business account.. my license are still pending due to this... I bank with ascend federal credit union it has a ZELLE for family. friends. ect. very low payments... the 2nd buyer did the exact same only he got a refund of close to 400. with ZELLE... at my checking he asked for 200 increments.. neverless.. I had only 3 usable check with TMobile and I paid bills but 175 +