Appears to be a classic case of overwatering. Or at least, not providing adequate drainage. The pot is still sitting in its foil wrapping. This should be removed as soon as the plant is brought home, as it will collect and retain water and impede good drainage. There may also be an issue with the soil media being overly moisture retentive - most prebagged mixes are.

Remove any dead or dying leaves, as they are not helping anything. I'd also unpot and examine the roots for rot or mushiness and then repot with a high quality, textural and fast draining potting soil.

I agree with all Pam said about the foil and over-watering, except that the damage looks to me more like chill injury or sunburn. Did you recently bring the plant into your home while temps were below freezing; or, perhaps set it in a full sun location for more than a half hour or so? Regardless, if either are the cause, there is nothing to be done about it other than removing the damaged leaves if they are too unsightly to tolerate, so reread Pam's advice about drainage and water retention.

Al