HTC — Mobile phone not repaired or replaced

I have submitted my mobile phone of HTC company to service centre for repair. first time there was display problem, i got back my phone after 15 days after getting repaired. when i got back my phone, within 1 day a new problem arises i.e lock button problem. i again submitted my device to the service centre. this time they took 20 day for repair. i made many phone calls to the company and they assured me i will get my phone after 100% quality checks. when i get back my phone, inspite of their 100% quality check a new problem arises, i.e speaker problem. this was now hardware problem. there is a lot of disturbances coming from speakers. i again submitted my device and about 25 days has been passed neither the comapny has repaired my phone nor they are replacing it. they are only saying me to wait wait and wait. my refrence ticket no. of all the three compalints are: 15INA[protected]INA[protected]INA[protected] NAME: PENNY ARORA MODEL: HTC DESIRE 816 DUAL SIM IMEI NO : [protected] THIRD TIME I HAVE SUBMITTED MY PHONE ON 29TH JULY 2015. PLEASE DO THE NEEDFUL.