Faulty Exercise Bike

We bought an exercise bike from MR Price on the 18th of January this year in August the bike didn't want to go to the hard levels when you cycle so I kept cycling n level 4-5 as that's the only levels I could go on. My husband lost the receipt so he went there with his bank statement and they said they could only exchange it and we were happy with that so they gave us a new one and told us that they could not reprint the receipt as it's some inhouse policy that they are not allowed to reprint the receipt but as I am cycling the bike makes a loud noise after cycling for 20 minutes, the hard levels on the bike are also not working efficiently, there is something wrong with the Maxed exercise bikes because this is a brand new bike but yet it's not working properly so all I want is my money back so that I can go purchase a different brand. I have a bench from MR Price and a few gym accessories and a treadmill, so I like the brand, but this bike is just not working.