Pathetic service

I'm really disappointed with RSAWEB, last week on the 2nd of July, I app**** for a speed upgrade from 25mb/s to 250mb/s they arranged to change my router and I called and asked if there's a technician that will come and do settings but the answer was no, I was told it's a plug and play, once I connect the new router the speed will go up, first few days the speed was good but from the beginning of this week my speed went back to 25mb/s, I don't know what to do anymore I've been calling their customer service but it doesn't look like they know what they're doing, I'm really disappointed with RSAWEB