The UPS Store review: dropping off packages from ups and usps

I would like to file a complaint about the store located at 3983 S McCarran Blvd, Reno, NV 89502. I do a lot of business with UPS and the post office. The store located above is closest to my business, so sometimes I drop off my UPS and USPS packages to them. Every time I drop off a UPS box or a bag of USPS packages, the staff seem to get upset or not like the fact that I am dropping off packages. I believe the reason is because some of the boxes I bring them are close to 50 lbs and the USPS bags have about 20-30 smaller packages in them. I know UPS has an agreement with the post office to accept these, so yesterday again I dropped off several UPS boxes, and 1 bag of USPS packages. The same staff member then proceeded to tell me that they can no longer accept my post office packages. I asked them why and they said because there was too many. So if I understand this correctly, I can drop off packages, but if I do too much business and bring too many packages, then that is not allowed. Please help me resolve this issue. Are they allowed to deny my packages? They are also extremely rude at that store and unfriendly to almost everyone. I know this is not the brand that UPS wants to reflect and uphold. I strongly suggest that someone look into this. Thank you for your time. I also am not one to goes to these lengths to file a complaint.