Booked a regular 4WD for pickup at the Dominica airport Monday. Upon pickup, we received a small 4WD with what felt like a 2-stroke engine and it really struggled just driving up hills on the regular roads of Dominica as we drove to our accom. Upon arrival at our accom, we found a rugged and rocky .8mi driveway that was difficult to handle in this small car, so we called Avis that night (Monday) to ask for a swap to a regular sized 4WD. They confirmed we could swap the car on Wednesday (1.5 days later). On Wednesday morning, Avis texted me at 837am to confirm a pickup time, for which we were flexible but asked to confirm a window between 12-2pm. Instead of driving an hour back to the airport, we were to drive an hour south to Roseau (which was fine as we had not yet seen that part of the island). We did not get a confirmed time back from Avis, so started the drive south with the hope they would confirm during our hour-long trip. Upon arrival, when we texted again, Avis confirmed a 230pm pickup time, but no location. We ended up going round and round in texts with time delays and location changes. Around 345pm, we finally were asked to meet at the Avis location in Roseau. After arriving 5mins later, the manager let us know that we would be getting a car from another rental company (as they weren't able to provide another vehicle directly), and that it would be another 5-10mins before the car arrived. The other car company rep arrived, with a bigger 4WD for us (with only 3/8 of a full tank), and we handled the paperwork within a few mins. We drove out of the Avis lot with the new car around 430pm, so the entire day time on Wednesday was dedicated to handling this car swap -- it was really frustrating. After the swap, our driving experience was much easier and the new car handled the hills and rugged terrain well. Upon arriving back at the Dominica airport at the end of our 7 day stay, we then had to pay a $20 toll to drive the car into the rental car parking lot to take it back -- this was not communicated to us at all, and was a small yet significant irritation regarding this car rental experience. If visiting again, I would book with a local car rental company, not Avis.